LO4.1 base gives wrong dates when connected to mysql database, all dates swich to 1/1/1800 or 1/1/2200 what happend?

the data in the database is not changed, but is not longer accessable thru the base form

I suggest to report a bug report to bugtracker: https://www.libreoffice.org/get-help/bug/?LOversion=
In bugtracker write exact version of software you are using and OS. In titlebar write down

[REGRESSION: Your title]

It would be helpful if you give some example. E.g. create table with few rows. And then write what you expect to get and what is the result. Please also report a bug number on this forum if other users have the same problem, to easily find out the info and add comments.