I found the problem. I thought that everything must be translated through po/mo files, but there is strings in the plugin’s settings, too. I am sorry for taking your time. Everything now is fine.
It’s ok, we can start again.
1. In wp-cofig define(‘WPLANG’, ‘’); = define(‘WPLANG’, ‘lv_LV’); and all other plugins read this very well.
2. In plugin’s ‘WordPress User Bookmarks for UserPro’ languages folder there is userpro-fav-en_US.po/mo file, I made a copy and translated to latvian, copied in teh same place with name: userpro-fav-lv_LV.po and userpro-fav-lv_LV.mo.
Strings are not translating.
What else I can do?
A.
Didn’t help 🙁 Any more ideas?
Sorry, didn’t, solved. Thank you!