Pull Request for Issue #28385 .

Summary of Changes

Use old pseudo null date in update script 4.0.0-2019-07-02.sql for checked out time, because the real null date value change is done with script 4.0.0-2019-10-06.sql, which runs after the previously mentioned one.

Testing Instructions

Has to be tested with MySQL (or MariaDB) and PostgreSQL.

Testers please report back which of these database types you have tested.

1. Install a fresh copy of 3.10 nightly or a git clone of the current 3.10-dev branch (it doesn't matter if with or without any testing sample data).
2. Go to the Joomla Update Component component config and set the URL to following custom URL: https://test5.richard-fath.de/next_major_list_pr-28391.xml, and the status to "development".
3. Update to Joomla 4.0.
4. When the update has finished, log in to backend.

Expected result

Update succeeds (except of the missing template message at the first login to the backend, which is normal).

Actual result

Update fails with SQL error "Column 'checked_out_time' cannot be null", and the CMS is broken, see issue #28385 .

Additional information

The diff clearly shows a difference between the update script for MySQL and the one for PostgreSQL in the ordering value for the inserted record.

For fixing such differences I am already on the way to prepare a PR, but it might be weekend until it will be ready.

Documentation Changes Required

None.