After Upgrade from version 3.50 to version 3.80 ceased to operate some functions in the administration (Configuration - Settings - General Settings), for example. 'Default theme store' and 'Store closed'. Do you have some experience with it, or even knows how to fix it? Thanks for every idea.
This is an old thread, but I will answer it for future users:
In version 3.80+, there is now a BASIC/ADVANCED switch at the top of admin pages. If features aren't visible to you, try switching to Advanced Mode.