diff --git a/python/educational-core/testData/migration/adaptive45.after.xml b/python/educational-core/testData/migration/adaptive45.after.xml
new file mode 100644
index 000000000000..cdb97a37db83
--- /dev/null
+++ b/python/educational-core/testData/migration/adaptive45.after.xml
@@ -0,0 +1,154 @@
+<component name="StudySettings">
+  <StudyTaskManager>
+    <option name="course">
+      <Course>
+        <option name="adaptive" value="true" />
+        <option name="authors">
+          <list>
+            <StepicUser>
+              <option name="accessToken" />
+              <option name="email" value="" />
+              <option name="firstName" value="" />
+              <option name="id" value="-1" />
+              <option name="lastName" value="" />
+              <option name="refreshToken" />
+            </StepicUser>
+          </list>
+        </option>
+        <option name="courseDirectory" value="$APPLICATION_CONFIG_DIR$/courses/__AdaptivePyCharmPython__test_adaptive_PyCharm_course_2_tuzova.k@gmail.com" />
+        <option name="courseMode" value="Study" />
+        <option name="courseType" value="PyCharm" />
+        <option name="description" value="This is a Stepik Adaptive course.&#10;&#10;Choice-test&#10;&#10;Initially, the adaptive system may behave somewhat randomly, but the more problems you solve, the smarter it become!" />
+        <option name="id" value="1730" />
+        <option name="language" value="Python" />
+        <option name="lessons">
+          <list>
+            <Lesson>
+              <option name="id" value="35738" />
+              <option name="index" value="1" />
+              <option name="name" value="Adaptive" />
+              <option name="updateDate" />
+              <option name="taskList">
+                <list>
+                  <CodeTask>
+                    <option name="activeSubtaskIndex" value="0" />
+                    <option name="index" value="1" />
+                    <option name="lastSubtaskIndex" value="0" />
+                    <option name="name" value="Hello world!" />
+                    <option name="status" value="Solved" />
+                    <option name="stepId" value="98994" />
+                    <option name="text" />
+                    <option name="updateDate" />
+                    <option name="taskFiles">
+                      <map>
+                        <entry key="code.py">
+                          <value>
+                            <TaskFile>
+                              <option name="answerPlaceholders">
+                                <list />
+                              </option>
+                              <option name="highlightErrors" value="true" />
+                              <option name="index" value="0" />
+                              <option name="trackChanges" value="true" />
+                              <option name="trackLengths" value="true" />
+                              <option name="userCreated" value="false" />
+                              <option name="name" value="code" />
+                              <option name="text" value="# put your python code here" />
+                            </TaskFile>
+                          </value>
+                        </entry>
+                      </map>
+                    </option>
+                  </CodeTask>
+                  <TheoryTask>
+                    <option name="activeSubtaskIndex" value="0" />
+                    <option name="index" value="2" />
+                    <option name="lastSubtaskIndex" value="0" />
+                    <option name="name" value="Theory. Input/output" />
+                    <option name="status" value="Solved" />
+                    <option name="stepId" value="131457" />
+                    <option name="text" />
+                    <option name="updateDate" />
+                    <option name="taskFiles">
+                      <map>
+                        <entry key="code.py">
+                          <value>
+                            <TaskFile>
+                              <option name="answerPlaceholders">
+                                <list />
+                              </option>
+                              <option name="highlightErrors" value="false" />
+                              <option name="index" value="0" />
+                              <option name="trackChanges" value="true" />
+                              <option name="trackLengths" value="true" />
+                              <option name="userCreated" value="false" />
+                              <option name="name" value="code" />
+                              <option name="text" value="# you can experiment here, it won't be checked" />
+                            </TaskFile>
+                          </value>
+                        </entry>
+                      </map>
+                    </option>
+                  </TheoryTask>
+                  <ChoiceTask>
+                    <option name="activeSubtaskIndex" value="0" />
+                    <option name="index" value="3" />
+                    <option name="lastSubtaskIndex" value="0" />
+                    <option name="name" value="Small question about functions" />
+                    <option name="status" value="Unchecked" />
+                    <option name="stepId" value="145807" />
+                    <option name="text" value="What does this function return?&lt;div&gt;&lt;br&gt;&lt;div&gt;&lt;pre&gt;&lt;pre&gt;&lt;code&gt;def f(a,b):&lt;br&gt; return a,b&lt;br&gt;&lt;br&gt;f(**{'b':2,'a':1})&lt;/code&gt;&lt;/pre&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;" />
+                    <option name="updateDate" />
+                    <option name="taskFiles">
+                      <map>
+                        <entry key="code.py">
+                          <value>
+                            <TaskFile>
+                              <option name="answerPlaceholders">
+                                <list />
+                              </option>
+                              <option name="highlightErrors" value="false" />
+                              <option name="index" value="0" />
+                              <option name="trackChanges" value="true" />
+                              <option name="trackLengths" value="true" />
+                              <option name="userCreated" value="false" />
+                              <option name="name" value="code" />
+                              <option name="text" value="# you can experiment here, it won't be checked" />
+                            </TaskFile>
+                          </value>
+                        </entry>
+                      </map>
+                    </option>
+                    <option name="choiceVariants">
+                      <list>
+                        <option value="(2, 1)" />
+                        <option value="It causes TypeError: f() got an unexpected keyword argument" />
+                        <option value="(1, 2)" />
+                      </list>
+                    </option>
+                    <option name="multipleChoice" value="false" />
+                    <option name="selectedVariants">
+                      <list />
+                    </option>
+                  </ChoiceTask>
+                </list>
+              </option>
+            </Lesson>
+          </list>
+        </option>
+        <option name="name" value="test_adaptive_PyCharm_course_2" />
+        <option name="updateDate" />
+      </Course>
+    </option>
+    <option name="toolWindowMode" value="TEXT" />
+    <option name="turnEditingMode" value="false" />
+    <option name="VERSION" value="4" />
+    <option name="myUserTests">
+      <map />
+    </option>
+    <option name="myInvisibleFiles">
+      <list />
+    </option>
+    <option name="myShouldUseJavaFx" value="true" />
+  </StudyTaskManager>
+</component>
\ No newline at end of file
diff --git a/python/educational-core/testData/migration/adaptive45.xml b/python/educational-core/testData/migration/adaptive45.xml
new file mode 100644
index 000000000000..e18194f223fc
--- /dev/null
+++ b/python/educational-core/testData/migration/adaptive45.xml
@@ -0,0 +1,175 @@
+<component name="StudySettings">
+  <StudyTaskManager>
+    <option name="course">
+      <Course>
+        <option name="adaptive" value="true" />
+        <option name="authors">
+          <list>
+            <StepicUser>
+              <option name="accessToken" />
+              <option name="email" value="" />
+              <option name="firstName" value="" />
+              <option name="id" value="-1" />
+              <option name="lastName" value="" />
+              <option name="refreshToken" />
+            </StepicUser>
+          </list>
+        </option>
+        <option name="courseDirectory" value="$APPLICATION_CONFIG_DIR$/courses/__AdaptivePyCharmPython__test_adaptive_PyCharm_course_2_tuzova.k@gmail.com" />
+        <option name="courseMode" value="Study" />
+        <option name="courseType" value="PyCharm" />
+        <option name="description" value="This is a Stepik Adaptive course.&#10;&#10;Choice-test&#10;&#10;Initially, the adaptive system may behave somewhat randomly, but the more problems you solve, the smarter it become!" />
+        <option name="id" value="1730" />
+        <option name="language" value="Python" />
+        <option name="lessons">
+          <list>
+            <Lesson>
+              <option name="id" value="35738" />
+              <option name="index" value="1" />
+              <option name="name" value="Adaptive" />
+              <option name="updateDate" />
+              <option name="taskList">
+                <list>
+                  <Task>
+                    <option name="activeSubtaskIndex" value="0" />
+                    <option name="adaptiveTaskParameters" />
+                    <option name="index" value="1" />
+                    <option name="lastSubtaskIndex" value="0" />
+                    <option name="name" value="Hello world!" />
+                    <option name="status" value="Solved" />
+                    <option name="stepId" value="98994" />
+                    <option name="text" />
+                    <option name="theoryTask" value="false" />
+                    <option name="updateDate" />
+                    <option name="taskFiles">
+                      <map>
+                        <entry key="code.py">
+                          <value>
+                            <TaskFile>
+                              <option name="answerPlaceholders">
+                                <list />
+                              </option>
+                              <option name="highlightErrors" value="true" />
+                              <option name="index" value="0" />
+                              <option name="trackChanges" value="true" />
+                              <option name="trackLengths" value="true" />
+                              <option name="userCreated" value="false" />
+                              <option name="name" value="code" />
+                              <option name="text" value="# put your python code here" />
+                            </TaskFile>
+                          </value>
+                        </entry>
+                      </map>
+                    </option>
+                  </Task>
+                  <Task>
+                    <option name="activeSubtaskIndex" value="0" />
+                    <option name="adaptiveTaskParameters">
+                      <AdaptiveTaskParameters>
+                        <option name="choiceVariants">
+                          <list />
+                        </option>
+                        <option name="multipleChoice" value="false" />
+                        <option name="selectedVariants">
+                          <list />
+                        </option>
+                        <option name="theoryTask" value="true" />
+                      </AdaptiveTaskParameters>
+                    </option>
+                    <option name="index" value="2" />
+                    <option name="lastSubtaskIndex" value="0" />
+                    <option name="name" value="Theory. Input/output" />
+                    <option name="status" value="Solved" />
+                    <option name="stepId" value="131457" />
+                    <option name="text" />
+                    <option name="theoryTask" value="true" />
+                    <option name="updateDate" />
+                    <option name="taskFiles">
+                      <map>
+                        <entry key="code.py">
+                          <value>
+                            <TaskFile>
+                              <option name="answerPlaceholders">
+                                <list />
+                              </option>
+                              <option name="highlightErrors" value="false" />
+                              <option name="index" value="0" />
+                              <option name="trackChanges" value="true" />
+                              <option name="trackLengths" value="true" />
+                              <option name="userCreated" value="false" />
+                              <option name="name" value="code" />
+                              <option name="text" value="# you can experiment here, it won't be checked" />
+                            </TaskFile>
+                          </value>
+                        </entry>
+                      </map>
+                    </option>
+                  </Task>
+                  <Task>
+                    <option name="activeSubtaskIndex" value="0" />
+                    <option name="adaptiveTaskParameters">
+                      <AdaptiveTaskParameters>
+                        <option name="choiceVariants">
+                          <list>
+                            <option value="(2, 1)" />
+                            <option value="It causes TypeError: f() got an unexpected keyword argument" />
+                            <option value="(1, 2)" />
+                          </list>
+                        </option>
+                        <option name="multipleChoice" value="false" />
+                        <option name="selectedVariants">
+                          <list />
+                        </option>
+                        <option name="theoryTask" value="false" />
+                      </AdaptiveTaskParameters>
+                    </option>
+                    <option name="index" value="3" />
+                    <option name="lastSubtaskIndex" value="0" />
+                    <option name="name" value="Small question about functions" />
+                    <option name="status" value="Unchecked" />
+                    <option name="stepId" value="145807" />
+                    <option name="text" value="What does this function return?&lt;div&gt;&lt;br&gt;&lt;div&gt;&lt;pre&gt;&lt;pre&gt;&lt;code&gt;def f(a,b):&lt;br&gt; return a,b&lt;br&gt;&lt;br&gt;f(**{'b':2,'a':1})&lt;/code&gt;&lt;/pre&gt;&lt;/pre&gt;&lt;/div&gt;&lt;/div&gt;" />
+                    <option name="theoryTask" value="false" />
+                    <option name="updateDate" />
+                    <option name="taskFiles">
+                      <map>
+                        <entry key="code.py">
+                          <value>
+                            <TaskFile>
+                              <option name="answerPlaceholders">
+                                <list />
+                              </option>
+                              <option name="highlightErrors" value="false" />
+                              <option name="index" value="0" />
+                              <option name="trackChanges" value="true" />
+                              <option name="trackLengths" value="true" />
+                              <option name="userCreated" value="false" />
+                              <option name="name" value="code" />
+                              <option name="text" value="# you can experiment here, it won't be checked" />
+                            </TaskFile>
+                          </value>
+                        </entry>
+                      </map>
+                    </option>
+                  </Task>
+                </list>
+              </option>
+            </Lesson>
+          </list>
+        </option>
+        <option name="name" value="test_adaptive_PyCharm_course_2" />
+        <option name="updateDate" />
+      </Course>
+    </option>
+    <option name="toolWindowMode" value="TEXT" />
+    <option name="turnEditingMode" value="false" />
+    <option name="VERSION" value="4" />
+    <option name="myUserTests">
+      <map />
+    </option>
+    <option name="myInvisibleFiles">
+      <list />
+    </option>
+    <option name="myShouldUseJavaFx" value="true" />
+  </StudyTaskManager>
+</component>
diff --git a/python/educational-core/testData/migration/fromThirdToForth.after.xml b/python/educational-core/testData/migration/fromThirdToForth.after.xml
new file mode 100644
index 000000000000..b0c11ff543b8
--- /dev/null
+++ b/python/educational-core/testData/migration/fromThirdToForth.after.xml
@@ -0,0 +1,131 @@
+<component name="StudySettings">
+  <StudyTaskManager>
+    <option name="course">
+      <Course>
+        <option name="adaptive" value="false"/>
+        <option name="authors">
+          <list>
+            <StepicUser>
+              <option name="email" value=""/>
+              <option name="firstName" value=""/>
+              <option name="id" value="-1"/>
+              <option name="lastName" value=""/>
+            </StepicUser>
+          </list>
+        </option>
+        <option name="courseDirectory" value="$APPLICATION_CONFIG_DIR$/courses/Introduction to Python"/>
+        <option name="courseMode" value="Study"/>
+        <option name="courseType" value="PyCharm"/>
+        <option name="description" value="Introduction course to Python"/>
+        <option name="id" value="238"/>
+        <option name="language" value="Python"/>
+        <option name="lessons">
+          <list>
+            <Lesson>
+              <option name="id" value="13416"/>
+              <option name="index" value="1"/>
+              <option name="name" value="Introduction"/>
+              <option name="updateDate"/>
+              <option name="taskList">
+                <list>
+                  <Task>
+                    <option name="index" value="1"/>
+                    <option name="name" value="Our first program"/>
+                    <option name="status" value="Solved"/>
+                    <option name="stepicId" value="98626"/>
+                    <option name="text"/>
+                    <option name="updateDate"/>
+                    <option name="taskFiles">
+                      <map>
+                        <entry key="hello_world.py">
+                          <value>
+                            <TaskFile>
+                              <option name="answerPlaceholders">
+                                <list>
+                                  <AnswerPlaceholder>
+                                    <option name="additionalHints">
+                                      <list>
+                                        <option value="hint 2"/>
+                                      </list>
+                                    </option>
+                                    <option name="hint" value="hint 1"/>
+                                    <option name="index" value="0"/>
+                                    <option name="initialState">
+                                      <MyInitialState>
+                                        <option name="length" value="14"/>
+                                        <option name="offset" value="32"/>
+                                      </MyInitialState>
+                                    </option>
+                                    <option name="length" value="5"/>
+                                    <option name="offset" value="32"/>
+                                    <option name="possibleAnswer" value="Liana"/>
+                                    <option name="selected" value="false"/>
+                                    <option name="status" value="Solved"/>
+                                    <option name="taskText" value="test text"/>
+                                    <option name="useLength" value="true"/>
+                                    <option name="subtaskInfos">
+                                      <map>
+                                        <entry key="0">
+                                          <value>
+                                            <AnswerPlaceholderSubtaskInfo>
+                                              <option name="hint" value="hint 1"/>
+                                              <option name="possibleAnswer" value="Liana"/>
+                                              <option name="selected" value="false"/>
+                                              <option name="status" value="Solved"/>
+                                              <option name="placeholderText" value="test text"/>
+                                              <option name="hints">
+                                                <list>
+                                                  <option value="hint 1"/>
+                                                  <option value="hint 2"/>
+                                                </list>
+                                              </option>
+                                            </AnswerPlaceholderSubtaskInfo>
+                                          </value>
+                                        </entry>
+                                      </map>
+                                    </option>
+                                  </AnswerPlaceholder>
+                                </list>
+                              </option>
+                              <option name="highlightErrors" value="true"/>
+                              <option name="index" value="0"/>
+                              <option name="trackChanges" value="true"/>
+                              <option name="userCreated" value="false"/>
+                              <option name="name" value="hello_world.py"/>
+                              <option name="text" value="print(&quot;Hello, world! My name is type your name&quot;)&#10;"/>
+                            </TaskFile>
+                          </value>
+                        </entry>
+                      </map>
+                    </option>
+                  </Task>
+                </list>
+              </option>
+            </Lesson>
+          </list>
+        </option>
+        <option name="name" value="Introduction to Python"/>
+        <option name="updateDate"/>
+      </Course>
+    </option>
+    <option name="enableTestingFromSamples" value="true"/>
+    <option name="toolWindowMode" value="TEXT"/>
+    <option name="turnEditingMode" value="false"/>
+    <option name="user">
+      <StepicUser>
+        <option name="email" value=""/>
+        <option name="firstName" value=""/>
+        <option name="id" value="-1"/>
+        <option name="lastName" value=""/>
+      </StepicUser>
+    </option>
+    <option name="VERSION" value="3"/>
+    <option name="myUserTests">
+      <map/>
+    </option>
+    <option name="myInvisibleFiles">
+      <list/>
+    </option>
+    <option name="myShouldUseJavaFx" value="true"/>
+  </StudyTaskManager>
+</component>
\ No newline at end of file
diff --git a/python/educational-core/testData/migration/fromThirdToForth.xml b/python/educational-core/testData/migration/fromThirdToForth.xml
new file mode 100644
index 000000000000..b347959a91f0
--- /dev/null
+++ b/python/educational-core/testData/migration/fromThirdToForth.xml
@@ -0,0 +1,110 @@
+<component name="StudySettings">
+  <StudyTaskManager>
+    <option name="course">
+      <Course>
+        <option name="adaptive" value="false"/>
+        <option name="authors">
+          <list>
+            <StepicUser>
+              <option name="email" value=""/>
+              <option name="firstName" value=""/>
+              <option name="id" value="-1"/>
+              <option name="lastName" value=""/>
+            </StepicUser>
+          </list>
+        </option>
+        <option name="courseDirectory" value="$APPLICATION_CONFIG_DIR$/courses/Introduction to Python"/>
+        <option name="courseMode" value="Study"/>
+        <option name="courseType" value="PyCharm"/>
+        <option name="description" value="Introduction course to Python"/>
+        <option name="id" value="238"/>
+        <option name="language" value="Python"/>
+        <option name="lessons">
+          <list>
+            <Lesson>
+              <option name="id" value="13416"/>
+              <option name="index" value="1"/>
+              <option name="name" value="Introduction"/>
+              <option name="updateDate"/>
+              <option name="taskList">
+                <list>
+                  <Task>
+                    <option name="index" value="1"/>
+                    <option name="name" value="Our first program"/>
+                    <option name="status" value="Solved"/>
+                    <option name="stepicId" value="98626"/>
+                    <option name="text"/>
+                    <option name="updateDate"/>
+                    <option name="taskFiles">
+                      <map>
+                        <entry key="hello_world.py">
+                          <value>
+                            <TaskFile>
+                              <option name="answerPlaceholders">
+                                <list>
+                                  <AnswerPlaceholder>
+                                    <option name="additionalHints">
+                                      <list>
+                                        <option value="hint 2"/>
+                                      </list>
+                                    </option>
+                                    <option name="hint" value="hint 1"/>
+                                    <option name="index" value="0"/>
+                                    <option name="initialState">
+                                      <MyInitialState>
+                                        <option name="length" value="14"/>
+                                        <option name="offset" value="32"/>
+                                      </MyInitialState>
+                                    </option>
+                                    <option name="length" value="5"/>
+                                    <option name="offset" value="32"/>
+                                    <option name="possibleAnswer" value="Liana"/>
+                                    <option name="selected" value="false"/>
+                                    <option name="status" value="Solved"/>
+                                    <option name="taskText" value="test text"/>
+                                    <option name="useLength" value="true"/>
+                                  </AnswerPlaceholder>
+                                </list>
+                              </option>
+                              <option name="highlightErrors" value="true"/>
+                              <option name="index" value="0"/>
+                              <option name="trackChanges" value="true"/>
+                              <option name="userCreated" value="false"/>
+                              <option name="name" value="hello_world.py"/>
+                              <option name="text" value="print(&quot;Hello, world! My name is type your name&quot;)&#10;"/>
+                            </TaskFile>
+                          </value>
+                        </entry>
+                      </map>
+                    </option>
+                  </Task>
+                </list>
+              </option>
+            </Lesson>
+          </list>
+        </option>
+        <option name="name" value="Introduction to Python"/>
+        <option name="updateDate"/>
+      </Course>
+    </option>
+    <option name="enableTestingFromSamples" value="true"/>
+    <option name="toolWindowMode" value="TEXT"/>
+    <option name="turnEditingMode" value="false"/>
+    <option name="user">
+      <StepicUser>
+        <option name="email" value=""/>
+        <option name="firstName" value=""/>
+        <option name="id" value="-1"/>
+        <option name="lastName" value=""/>
+      </StepicUser>
+    </option>
+    <option name="VERSION" value="3"/>
+    <option name="myUserTests">
+      <map/>
+    </option>
+    <option name="myInvisibleFiles">
+      <list/>
+    </option>
+    <option name="myShouldUseJavaFx" value="true"/>
+  </StudyTaskManager>
+</component>
\ No newline at end of file
diff --git a/python/educational-core/testData/migration/subtasks45.after.xml b/python/educational-core/testData/migration/subtasks45.after.xml
new file mode 100644
index 000000000000..e11207ce1d0c
--- /dev/null
+++ b/python/educational-core/testData/migration/subtasks45.after.xml
@@ -0,0 +1,145 @@
+<component name="StudySettings">
+  <StudyTaskManager>
+    <option name="course">
+      <Course>
+        <option name="adaptive" value="false" />
+        <option name="authors">
+          <list>
+            <StepicUser>
+              <option name="accessToken" />
+              <option name="email" value="" />
+              <option name="firstName" value="ktisha" />
+              <option name="id" value="-1" />
+              <option name="lastName" value="" />
+              <option name="refreshToken" />
+            </StepicUser>
+          </list>
+        </option>
+        <option name="courseDirectory" value="$APPLICATION_CONFIG_DIR$/courses/1234-untitled" />
+        <option name="courseMode" value="Course Creator" />
+        <option name="courseType" value="PyCharm" />
+        <option name="description" value="qwer" />
+        <option name="id" value="0" />
+        <option name="language" value="Python" />
+        <option name="lessons">
+          <list>
+            <Lesson>
+              <option name="id" value="0" />
+              <option name="index" value="1" />
+              <option name="name" value="lesson1" />
+              <option name="updateDate" />
+              <option name="taskList">
+                <list>
+                  <TaskWithSubtasks>
+                    <option name="activeSubtaskIndex" value="1" />
+                    <option name="index" value="1" />
+                    <option name="lastSubtaskIndex" value="1" />
+                    <option name="name" value="task1" />
+                    <option name="status" value="Unchecked" />
+                    <option name="stepId" value="0" />
+                    <option name="text" />
+                    <option name="updateDate" />
+                    <option name="taskFiles">
+                      <map>
+                        <entry key="task.py">
+                          <value>
+                            <TaskFile>
+                              <option name="answerPlaceholders">
+                                <list>
+                                  <AnswerPlaceholder>
+                                    <option name="index" value="0" />
+                                    <option name="initialState" />
+                                    <option name="length" value="3" />
+                                    <option name="offset" value="7" />
+                                    <option name="selected" value="false" />
+                                    <option name="subtaskInfos">
+                                      <map>
+                                        <entry key="0">
+                                          <value>
+                                            <AnswerPlaceholderSubtaskInfo>
+                                              <option name="answer" value="" />
+                                              <option name="hasFrame" value="true" />
+                                              <option name="hints">
+                                                <list>
+                                                  <option value="hint1" />
+                                                </list>
+                                              </option>
+                                              <option name="needInsertText" value="false" />
+                                              <option name="placeholderText" value="123" />
+                                              <option name="possibleAnswer" value=" type" />
+                                              <option name="selected" value="false" />
+                                              <option name="status" value="Unchecked" />
+                                            </AnswerPlaceholderSubtaskInfo>
+                                          </value>
+                                        </entry>
+                                      </map>
+                                    </option>
+                                    <option name="useLength" value="false" />
+                                  </AnswerPlaceholder>
+                                  <AnswerPlaceholder>
+                                    <option name="index" value="1" />
+                                    <option name="initialState" />
+                                    <option name="length" value="4" />
+                                    <option name="offset" value="22" />
+                                    <option name="selected" value="false" />
+                                    <option name="subtaskInfos">
+                                      <map>
+                                        <entry key="1">
+                                          <value>
+                                            <AnswerPlaceholderSubtaskInfo>
+                                              <option name="answer" value="" />
+                                              <option name="hasFrame" value="true" />
+                                              <option name="hints">
+                                                <list>
+                                                  <option value="hint2" />
+                                                </list>
+                                              </option>
+                                              <option name="needInsertText" value="false" />
+                                              <option name="placeholderText" value="zxcv" />
+                                              <option name="possibleAnswer" value="here" />
+                                              <option name="selected" value="false" />
+                                              <option name="status" value="Unchecked" />
+                                            </AnswerPlaceholderSubtaskInfo>
+                                          </value>
+                                        </entry>
+                                      </map>
+                                    </option>
+                                    <option name="useLength" value="false" />
+                                  </AnswerPlaceholder>
+                                </list>
+                              </option>
+                              <option name="highlightErrors" value="true" />
+                              <option name="index" value="1" />
+                              <option name="trackChanges" value="true" />
+                              <option name="trackLengths" value="true" />
+                              <option name="userCreated" value="false" />
+                              <option name="name" value="task.py" />
+                              <option name="text" />
+                            </TaskFile>
+                          </value>
+                        </entry>
+                      </map>
+                    </option>
+                  </TaskWithSubtasks>
+                </list>
+              </option>
+            </Lesson>
+          </list>
+        </option>
+        <option name="name" value="1234" />
+        <option name="updateDate" />
+      </Course>
+    </option>
+    <option name="enableTestingFromSamples" value="false" />
+    <option name="toolWindowMode" value="TEXT" />
+    <option name="turnEditingMode" value="false" />
+    <option name="VERSION" value="4" />
+    <option name="myUserTests">
+      <map />
+    </option>
+    <option name="myInvisibleFiles">
+      <list />
+    </option>
+    <option name="myShouldUseJavaFx" value="true" />
+  </StudyTaskManager>
+</component>
\ No newline at end of file
diff --git a/python/educational-core/testData/migration/subtasks45.xml b/python/educational-core/testData/migration/subtasks45.xml
new file mode 100644
index 000000000000..b8a4ca5b482d
--- /dev/null
+++ b/python/educational-core/testData/migration/subtasks45.xml
@@ -0,0 +1,158 @@
+<component name="StudySettings">
+  <StudyTaskManager>
+    <option name="course">
+      <Course>
+        <option name="adaptive" value="false" />
+        <option name="authors">
+          <list>
+            <StepicUser>
+              <option name="accessToken" />
+              <option name="email" value="" />
+              <option name="firstName" value="ktisha" />
+              <option name="id" value="-1" />
+              <option name="lastName" value="" />
+              <option name="refreshToken" />
+            </StepicUser>
+          </list>
+        </option>
+        <option name="courseDirectory" value="$APPLICATION_CONFIG_DIR$/courses/1234-untitled" />
+        <option name="courseMode" value="Course Creator" />
+        <option name="courseType" value="PyCharm" />
+        <option name="description" value="qwer" />
+        <option name="id" value="0" />
+        <option name="language" value="Python" />
+        <option name="lessons">
+          <list>
+            <Lesson>
+              <option name="id" value="0" />
+              <option name="index" value="1" />
+              <option name="name" value="lesson1" />
+              <option name="updateDate" />
+              <option name="taskList">
+                <list>
+                  <Task>
+                    <option name="activeSubtaskIndex" value="1" />
+                    <option name="adaptiveTaskParameters">
+                      <AdaptiveTaskParameters>
+                        <option name="choiceVariants">
+                          <list />
+                        </option>
+                        <option name="multipleChoice" value="false" />
+                        <option name="selectedVariants">
+                          <list />
+                        </option>
+                        <option name="theoryTask" value="false" />
+                      </AdaptiveTaskParameters>
+                    </option>
+                    <option name="index" value="1" />
+                    <option name="lastSubtaskIndex" value="1" />
+                    <option name="name" value="task1" />
+                    <option name="status" value="Unchecked" />
+                    <option name="stepId" value="0" />
+                    <option name="text" />
+                    <option name="theoryTask" value="false" />
+                    <option name="updateDate" />
+                    <option name="taskFiles">
+                      <map>
+                        <entry key="task.py">
+                          <value>
+                            <TaskFile>
+                              <option name="answerPlaceholders">
+                                <list>
+                                  <AnswerPlaceholder>
+                                    <option name="index" value="0" />
+                                    <option name="initialState" />
+                                    <option name="length" value="3" />
+                                    <option name="offset" value="7" />
+                                    <option name="selected" value="false" />
+                                    <option name="subtaskInfos">
+                                      <map>
+                                        <entry key="0">
+                                          <value>
+                                            <AnswerPlaceholderSubtaskInfo>
+                                              <option name="answer" value="" />
+                                              <option name="hasFrame" value="true" />
+                                              <option name="hints">
+                                                <list>
+                                                  <option value="hint1" />
+                                                </list>
+                                              </option>
+                                              <option name="needInsertText" value="false" />
+                                              <option name="placeholderText" value="123" />
+                                              <option name="possibleAnswer" value=" type" />
+                                              <option name="selected" value="false" />
+                                              <option name="status" value="Unchecked" />
+                                            </AnswerPlaceholderSubtaskInfo>
+                                          </value>
+                                        </entry>
+                                      </map>
+                                    </option>
+                                    <option name="useLength" value="false" />
+                                  </AnswerPlaceholder>
+                                  <AnswerPlaceholder>
+                                    <option name="index" value="1" />
+                                    <option name="initialState" />
+                                    <option name="length" value="4" />
+                                    <option name="offset" value="22" />
+                                    <option name="selected" value="false" />
+                                    <option name="subtaskInfos">
+                                      <map>
+                                        <entry key="1">
+                                          <value>
+                                            <AnswerPlaceholderSubtaskInfo>
+                                              <option name="answer" value="" />
+                                              <option name="hasFrame" value="true" />
+                                              <option name="hints">
+                                                <list>
+                                                  <option value="hint2" />
+                                                </list>
+                                              </option>
+                                              <option name="needInsertText" value="false" />
+                                              <option name="placeholderText" value="zxcv" />
+                                              <option name="possibleAnswer" value="here" />
+                                              <option name="selected" value="false" />
+                                              <option name="status" value="Unchecked" />
+                                            </AnswerPlaceholderSubtaskInfo>
+                                          </value>
+                                        </entry>
+                                      </map>
+                                    </option>
+                                    <option name="useLength" value="false" />
+                                  </AnswerPlaceholder>
+                                </list>
+                              </option>
+                              <option name="highlightErrors" value="true" />
+                              <option name="index" value="1" />
+                              <option name="trackChanges" value="true" />
+                              <option name="trackLengths" value="true" />
+                              <option name="userCreated" value="false" />
+                              <option name="name" value="task.py" />
+                              <option name="text" />
+                            </TaskFile>
+                          </value>
+                        </entry>
+                      </map>
+                    </option>
+                  </Task>
+                </list>
+              </option>
+            </Lesson>
+          </list>
+        </option>
+        <option name="name" value="1234" />
+        <option name="updateDate" />
+      </Course>
+    </option>
+    <option name="enableTestingFromSamples" value="false" />
+    <option name="toolWindowMode" value="TEXT" />
+    <option name="turnEditingMode" value="false" />
+    <option name="VERSION" value="4" />
+    <option name="myUserTests">
+      <map />
+    </option>
+    <option name="myInvisibleFiles">
+      <list />
+    </option>
+    <option name="myShouldUseJavaFx" value="true" />
+  </StudyTaskManager>
+</component>
\ No newline at end of file
diff --git a/python/educational-core/testData/migration/theory351To4.after.xml b/python/educational-core/testData/migration/theory351To4.after.xml
new file mode 100644
index 000000000000..88c6f6a616de
--- /dev/null
+++ b/python/educational-core/testData/migration/theory351To4.after.xml
@@ -0,0 +1,115 @@
+<component name="StudySettings">
+  <StudyTaskManager>
+    <option name="course">
+      <Course>
+        <option name="adaptive" value="false" />
+        <option name="authors">
+          <list>
+            <StepicUser>
+              <option name="accessToken" />
+              <option name="email" value="" />
+              <option name="firstName" value="ktisha" />
+              <option name="id" value="-1" />
+              <option name="lastName" value="" />
+              <option name="refreshToken" />
+            </StepicUser>
+          </list>
+        </option>
+        <option name="courseDirectory" value="$APPLICATION_CONFIG_DIR$/courses/test-untitled31" />
+        <option name="courseMode" value="Course Creator" />
+        <option name="courseType" value="PyCharm" />
+        <option name="description" value="test project" />
+        <option name="id" value="0" />
+        <option name="language" value="Python" />
+        <option name="lessons">
+          <list>
+            <Lesson>
+              <option name="id" value="0" />
+              <option name="index" value="1" />
+              <option name="name" value="lesson1" />
+              <option name="updateDate" />
+              <option name="taskList">
+                <list>
+                  <Task>
+                    <option name="activeSubtaskIndex" value="0" />
+                    <option name="index" value="1" />
+                    <option name="lastSubtaskIndex" value="0" />
+                    <option name="name" value="task1" />
+                    <option name="status" value="Unchecked" />
+                    <option name="stepId" value="0" />
+                    <option name="text" />
+                    <option name="updateDate" />
+                    <option name="taskFiles">
+                      <map>
+                        <entry key="task.py">
+                          <value>
+                            <TaskFile>
+                              <option name="answerPlaceholders">
+                                <list>
+                                  <AnswerPlaceholder>
+                                    <option name="index" value="0" />
+                                    <option name="initialState" />
+                                    <option name="length" value="4" />
+                                    <option name="offset" value="42" />
+                                    <option name="selected" value="false" />
+                                    <option name="subtaskInfos">
+                                      <map>
+                                        <entry key="0">
+                                          <value>
+                                            <AnswerPlaceholderSubtaskInfo>
+                                              <option name="answer" value="" />
+                                              <option name="hasFrame" value="true" />
+                                              <option name="hints">
+                                                <list>
+                                                  <option value="hint" />
+                                                </list>
+                                              </option>
+                                              <option name="needInsertText" value="false" />
+                                              <option name="placeholderText" value="type" />
+                                              <option name="possibleAnswer" value="pass" />
+                                              <option name="selected" value="false" />
+                                              <option name="status" value="Unchecked" />
+                                            </AnswerPlaceholderSubtaskInfo>
+                                          </value>
+                                        </entry>
+                                      </map>
+                                    </option>
+                                    <option name="useLength" value="false" />
+                                  </AnswerPlaceholder>
+                                </list>
+                              </option>
+                              <option name="highlightErrors" value="true" />
+                              <option name="index" value="1" />
+                              <option name="trackChanges" value="true" />
+                              <option name="trackLengths" value="true" />
+                              <option name="userCreated" value="false" />
+                              <option name="name" value="task.py" />
+                              <option name="text" />
+                            </TaskFile>
+                          </value>
+                        </entry>
+                      </map>
+                    </option>
+                  </Task>
+                </list>
+              </option>
+            </Lesson>
+          </list>
+        </option>
+        <option name="name" value="test" />
+        <option name="updateDate" />
+      </Course>
+    </option>
+    <option name="enableTestingFromSamples" value="false" />
+    <option name="toolWindowMode" value="TEXT" />
+    <option name="turnEditingMode" value="false" />
+    <option name="VERSION" value="4" />
+    <option name="myUserTests">
+      <map />
+    </option>
+    <option name="myInvisibleFiles">
+      <list />
+    </option>
+    <option name="myShouldUseJavaFx" value="true" />
+  </StudyTaskManager>
+</component>
\ No newline at end of file
diff --git a/python/educational-core/testData/migration/theory351To4.xml b/python/educational-core/testData/migration/theory351To4.xml
new file mode 100644
index 000000000000..205453ac34d0
--- /dev/null
+++ b/python/educational-core/testData/migration/theory351To4.xml
@@ -0,0 +1,117 @@
+<component name="StudySettings">
+  <StudyTaskManager>
+    <option name="course">
+      <Course>
+        <option name="adaptive" value="false" />
+        <option name="authors">
+          <list>
+            <StepicUser>
+              <option name="accessToken" />
+              <option name="email" value="" />
+              <option name="firstName" value="ktisha" />
+              <option name="id" value="-1" />
+              <option name="lastName" value="" />
+              <option name="refreshToken" />
+            </StepicUser>
+          </list>
+        </option>
+        <option name="courseDirectory" value="$APPLICATION_CONFIG_DIR$/courses/test-untitled31" />
+        <option name="courseMode" value="Course Creator" />
+        <option name="courseType" value="PyCharm" />
+        <option name="description" value="test project" />
+        <option name="id" value="0" />
+        <option name="language" value="Python" />
+        <option name="lessons">
+          <list>
+            <Lesson>
+              <option name="id" value="0" />
+              <option name="index" value="1" />
+              <option name="name" value="lesson1" />
+              <option name="updateDate" />
+              <option name="taskList">
+                <list>
+                  <Task>
+                    <option name="activeSubtaskIndex" value="0" />
+                    <option name="adaptiveTaskParameters" />
+                    <option name="index" value="1" />
+                    <option name="lastSubtaskIndex" value="0" />
+                    <option name="name" value="task1" />
+                    <option name="status" value="Unchecked" />
+                    <option name="stepId" value="0" />
+                    <option name="text" />
+                    <option name="theoryTask" value="false" />
+                    <option name="updateDate" />
+                    <option name="taskFiles">
+                      <map>
+                        <entry key="task.py">
+                          <value>
+                            <TaskFile>
+                              <option name="answerPlaceholders">
+                                <list>
+                                  <AnswerPlaceholder>
+                                    <option name="index" value="0" />
+                                    <option name="initialState" />
+                                    <option name="length" value="4" />
+                                    <option name="offset" value="42" />
+                                    <option name="selected" value="false" />
+                                    <option name="subtaskInfos">
+                                      <map>
+                                        <entry key="0">
+                                          <value>
+                                            <AnswerPlaceholderSubtaskInfo>
+                                              <option name="answer" value="" />
+                                              <option name="hasFrame" value="true" />
+                                              <option name="hints">
+                                                <list>
+                                                  <option value="hint" />
+                                                </list>
+                                              </option>
+                                              <option name="needInsertText" value="false" />
+                                              <option name="placeholderText" value="type" />
+                                              <option name="possibleAnswer" value="pass" />
+                                              <option name="selected" value="false" />
+                                              <option name="status" value="Unchecked" />
+                                            </AnswerPlaceholderSubtaskInfo>
+                                          </value>
+                                        </entry>
+                                      </map>
+                                    </option>
+                                    <option name="useLength" value="false" />
+                                  </AnswerPlaceholder>
+                                </list>
+                              </option>
+                              <option name="highlightErrors" value="true" />
+                              <option name="index" value="1" />
+                              <option name="trackChanges" value="true" />
+                              <option name="trackLengths" value="true" />
+                              <option name="userCreated" value="false" />
+                              <option name="name" value="task.py" />
+                              <option name="text" />
+                            </TaskFile>
+                          </value>
+                        </entry>
+                      </map>
+                    </option>
+                  </Task>
+                </list>
+              </option>
+            </Lesson>
+          </list>
+        </option>
+        <option name="name" value="test" />
+        <option name="updateDate" />
+      </Course>
+    </option>
+    <option name="enableTestingFromSamples" value="false" />
+    <option name="toolWindowMode" value="TEXT" />
+    <option name="turnEditingMode" value="false" />
+    <option name="VERSION" value="4" />
+    <option name="myUserTests">
+      <map />
+    </option>
+    <option name="myInvisibleFiles">
+      <list />
+    </option>
+    <option name="myShouldUseJavaFx" value="true" />
+  </StudyTaskManager>
+</component>
\ No newline at end of file
diff --git a/python/educational-core/testData/migration/theory35To4.after.xml b/python/educational-core/testData/migration/theory35To4.after.xml
new file mode 100644
index 000000000000..07edf716d6b2
--- /dev/null
+++ b/python/educational-core/testData/migration/theory35To4.after.xml
@@ -0,0 +1,115 @@
+<component name="StudySettings">
+  <StudyTaskManager>
+    <option name="course">
+      <Course>
+        <option name="adaptive" value="false" />
+        <option name="authors">
+          <list>
+            <StepicUser>
+              <option name="accessToken" />
+              <option name="email" value="" />
+              <option name="firstName" value="ktisha" />
+              <option name="id" value="-1" />
+              <option name="lastName" value="" />
+              <option name="refreshToken" />
+            </StepicUser>
+          </list>
+        </option>
+        <option name="courseDirectory" value="$APPLICATION_CONFIG_DIR$/courses/test-untitled30" />
+        <option name="courseMode" value="Course Creator" />
+        <option name="courseType" value="PyCharm" />
+        <option name="description" value="test project" />
+        <option name="id" value="0" />
+        <option name="language" value="Python" />
+        <option name="lessons">
+          <list>
+            <Lesson>
+              <option name="id" value="0" />
+              <option name="index" value="1" />
+              <option name="name" value="lesson1" />
+              <option name="updateDate" />
+              <option name="taskList">
+                <list>
+                  <Task>
+                    <option name="activeSubtaskIndex" value="0" />
+                    <option name="index" value="1" />
+                    <option name="lastSubtaskIndex" value="0" />
+                    <option name="name" value="task1" />
+                    <option name="status" value="Unchecked" />
+                    <option name="stepId" value="0" />
+                    <option name="text" />
+                    <option name="updateDate" />
+                    <option name="taskFiles">
+                      <map>
+                        <entry key="task.py">
+                          <value>
+                            <TaskFile>
+                              <option name="answerPlaceholders">
+                                <list>
+                                  <AnswerPlaceholder>
+                                    <option name="index" value="0" />
+                                    <option name="initialState" />
+                                    <option name="length" value="5" />
+                                    <option name="offset" value="42" />
+                                    <option name="selected" value="false" />
+                                    <option name="subtaskInfos">
+                                      <map>
+                                        <entry key="0">
+                                          <value>
+                                            <AnswerPlaceholderSubtaskInfo>
+                                              <option name="answer" value="" />
+                                              <option name="hasFrame" value="true" />
+                                              <option name="hints">
+                                                <list>
+                                                  <option value="hint1" />
+                                                </list>
+                                              </option>
+                                              <option name="needInsertText" value="false" />
+                                              <option name="placeholderText" value="place" />
+                                              <option name="possibleAnswer" value="pass" />
+                                              <option name="selected" value="false" />
+                                              <option name="status" value="Unchecked" />
+                                            </AnswerPlaceholderSubtaskInfo>
+                                          </value>
+                                        </entry>
+                                      </map>
+                                    </option>
+                                    <option name="useLength" value="false" />
+                                  </AnswerPlaceholder>
+                                </list>
+                              </option>
+                              <option name="highlightErrors" value="true" />
+                              <option name="index" value="1" />
+                              <option name="trackChanges" value="true" />
+                              <option name="trackLengths" value="true" />
+                              <option name="userCreated" value="false" />
+                              <option name="name" value="task.py" />
+                              <option name="text" />
+                            </TaskFile>
+                          </value>
+                        </entry>
+                      </map>
+                    </option>
+                  </Task>
+                </list>
+              </option>
+            </Lesson>
+          </list>
+        </option>
+        <option name="name" value="test" />
+        <option name="updateDate" />
+      </Course>
+    </option>
+    <option name="enableTestingFromSamples" value="false" />
+    <option name="toolWindowMode" value="TEXT" />
+    <option name="turnEditingMode" value="false" />
+    <option name="VERSION" value="4" />
+    <option name="myUserTests">
+      <map />
+    </option>
+    <option name="myInvisibleFiles">
+      <list />
+    </option>
+    <option name="myShouldUseJavaFx" value="true" />
+  </StudyTaskManager>
+</component>
\ No newline at end of file
diff --git a/python/educational-core/testData/migration/theory35To4.xml b/python/educational-core/testData/migration/theory35To4.xml
new file mode 100644
index 000000000000..408fd6301eef
--- /dev/null
+++ b/python/educational-core/testData/migration/theory35To4.xml
@@ -0,0 +1,117 @@
+<component name="StudySettings">
+  <StudyTaskManager>
+    <option name="course">
+      <Course>
+        <option name="adaptive" value="false" />
+        <option name="authors">
+          <list>
+            <StepicUser>
+              <option name="accessToken" />
+              <option name="email" value="" />
+              <option name="firstName" value="ktisha" />
+              <option name="id" value="-1" />
+              <option name="lastName" value="" />
+              <option name="refreshToken" />
+            </StepicUser>
+          </list>
+        </option>
+        <option name="courseDirectory" value="$APPLICATION_CONFIG_DIR$/courses/test-untitled30" />
+        <option name="courseMode" value="Course Creator" />
+        <option name="courseType" value="PyCharm" />
+        <option name="description" value="test project" />
+        <option name="id" value="0" />
+        <option name="language" value="Python" />
+        <option name="lessons">
+          <list>
+            <Lesson>
+              <option name="id" value="0" />
+              <option name="index" value="1" />
+              <option name="name" value="lesson1" />
+              <option name="updateDate" />
+              <option name="taskList">
+                <list>
+                  <Task>
+                    <option name="activeSubtaskIndex" value="0" />
+                    <option name="adaptiveTaskParameters" />
+                    <option name="index" value="1" />
+                    <option name="lastSubtaskIndex" value="0" />
+                    <option name="name" value="task1" />
+                    <option name="status" value="Unchecked" />
+                    <option name="stepId" value="0" />
+                    <option name="text" />
+                    <option name="theoryTask" value="false" />
+                    <option name="updateDate" />
+                    <option name="taskFiles">
+                      <map>
+                        <entry key="task.py">
+                          <value>
+                            <TaskFile>
+                              <option name="answerPlaceholders">
+                                <list>
+                                  <AnswerPlaceholder>
+                                    <option name="index" value="0" />
+                                    <option name="initialState" />
+                                    <option name="length" value="5" />
+                                    <option name="offset" value="42" />
+                                    <option name="selected" value="false" />
+                                    <option name="subtaskInfos">
+                                      <map>
+                                        <entry key="0">
+                                          <value>
+                                            <AnswerPlaceholderSubtaskInfo>
+                                              <option name="answer" value="" />
+                                              <option name="hasFrame" value="true" />
+                                              <option name="hints">
+                                                <list>
+                                                  <option value="hint1" />
+                                                </list>
+                                              </option>
+                                              <option name="needInsertText" value="false" />
+                                              <option name="placeholderText" value="place" />
+                                              <option name="possibleAnswer" value="pass" />
+                                              <option name="selected" value="false" />
+                                              <option name="status" value="Unchecked" />
+                                            </AnswerPlaceholderSubtaskInfo>
+                                          </value>
+                                        </entry>
+                                      </map>
+                                    </option>
+                                    <option name="useLength" value="false" />
+                                  </AnswerPlaceholder>
+                                </list>
+                              </option>
+                              <option name="highlightErrors" value="true" />
+                              <option name="index" value="1" />
+                              <option name="trackChanges" value="true" />
+                              <option name="trackLengths" value="true" />
+                              <option name="userCreated" value="false" />
+                              <option name="name" value="task.py" />
+                              <option name="text" />
+                            </TaskFile>
+                          </value>
+                        </entry>
+                      </map>
+                    </option>
+                  </Task>
+                </list>
+              </option>
+            </Lesson>
+          </list>
+        </option>
+        <option name="name" value="test" />
+        <option name="updateDate" />
+      </Course>
+    </option>
+    <option name="enableTestingFromSamples" value="false" />
+    <option name="toolWindowMode" value="TEXT" />
+    <option name="turnEditingMode" value="false" />
+    <option name="VERSION" value="4" />
+    <option name="myUserTests">
+      <map />
+    </option>
+    <option name="myInvisibleFiles">
+      <list />
+    </option>
+    <option name="myShouldUseJavaFx" value="true" />
+  </StudyTaskManager>
+</component>