Looking at my question, i was not clear. The problems started after FreePBX modules got updated. Last week there were Core, Endpoint and some other. The problems started after updating them. The core OS has not had updates in months.
@danardf this system is FreePBX 13, based on CentOS 6 and that package is for 7. I found it for 6 and will do tests.
@dicko i already did check that. The database is as it has been for a couple of months, utf8. No changes there.
For the problem with Incorrect string value , on other systems (not FreePBX) people are converting their utf8 tables to utf8mb4 in order to hold the 4-byte UTF8 strings.
Maybe i should try that?
One other option is to rename all my extensions back to English, which would be ugly for my users.
Other option is to go back to older Core, before last week’s updates, if that’s possible.