Error after version 2.6 update

[support]

Lets try another fix. File from archive replace to includes\classes\fieldstypes\
Let me know if it works ok now.

[AchLive]

Hi Sergey, thanks for the reply.
Now works!
Ultimately to solve the problem you need to replace the files that you have included in the "model2.zip" package and in the "fieldtype_dropdown_multilevel.zip" package? If I replace only the "fieldtype_dropdown_multilevel.zip" package file the problem remains.
Will we find all these files in the next update?
Thanks for the support

[support]

all this fixes will be included in next release.