Well, the next try

my provider offered a transfer to a new database with MYSQL 5.7 (also possible MYSQL 8, or MariaDB 10.6) and I tried the update. I got these errors:

Fehler!

    Database error in line 363: Incorrect datetime value: '0000-00-00 00:00:00' for column 'edited' at row 1
    Database error in line 378: Incorrect date value: '0000-00-00' for column 'birthday' at row 1
    Database error in line 381: Incorrect date value: '0000-00-00' for column 'birthday' at row 1

The forum itself seems to run, however it shown ugly PHP warnings:

Warning: mysqli_fetch_row() expects parameter 1 to be mysqli_result, boolean given in /PATH/includes/main.inc.php on line 259

Warning: mysqli_free_result() expects parameter 1 to be mysqli_result, boolean given in /PATH/forum/includes/main.inc.php on line 260

Warning: mysqli_fetch_row() expects parameter 1 to be mysqli_result, boolean given in /PATH/forum/includes/main.inc.php on line 262

Warning: mysqli_free_result() expects parameter 1 to be mysqli_result, boolean given in /PATH/forum/includes/main.inc.php on line 263

Warning: mysqli_fetch_row() expects parameter 1 to be mysqli_result, boolean given in /PATH/forum/includes/main.inc.php on line 267

Warning: mysqli_free_result() expects parameter 1 to be mysqli_result, boolean given in /PATH/forum/includes/main.inc.php on line 268

Warning: Cannot modify header information - headers already sent by (output started at /PATH/forum/includes/main.inc.php:259) in /PATH/forum/index.php on line 208

Warning: Cannot modify header information - headers already sent by (output started at /PATH/forum/includes/main.inc.php:259) in /PATH/forum/index.php on line 209

remarks:

- Before the update attempt today the forum was O.K., but I did a similar try two weeks ago. I cannot confirm that this try did not touch the databases. However this should be unlikely.

- In the "entries" table there are entries with "0000-00-00 00:00:00" in the edited row.

- in the "uderdata" table there are entries with "0000-00-00" in the borthday row.

Should I set these entries to NULL manually before updating?

Any suggestions?