During upgrade from version 9.4.7 to version 10.2.0 NullPointerException is being thrown in line 6220 of DataMigrator.java (method migrate156). Most likely userSearchBaseElement variable is null in our case, as our authenticator plugin is not using userSearchBase property at all. It is not possible to fix that by modification of Settings.xml as it fails to load as our authenticator class is missing that field.

Would it be possible to make this following part of the code conditional?, ie. in the following way:

var userSearchBaseElement = valueElement.element("userSearchBase");
if (userSearchBaseElement != null) {
    valueElement.addElement("userSearchBases").addElement("string").setText(userSearchBaseElement.getText().trim());
    userSearchBaseElement.detach();
}

it should make upgrade of this field executed only if this field actually exists.