activeCollab works on MySQL5, but you may experience problems on some rare situations if you have it running in strict SQL mode. It is advised to use a less strict SQL mode (MYSQL40 mode is recommended).
There are two ways to change the value of SQL mode preference:
SET @@global.sql_mode='MYSQL40'
sql-mode="MYSQL40"
You should then save the my.cnf file and restart the MySQL server.
To verify that the SQL mode has been updated, execute the following command:
SELECT @@global.sql_mode;
MySQL should then return something like this:
NO_FIELD_OPTIONS,MYSQL40,HIGH_NOT_PRECEDENCE