Upgrading ToolsTalk2 from 2.20 to 2.21

Before start of the upgrade, make sure that:

the ToolsTalk2 server runs.
a backup of the database is done.
the installation of ACDC is version 2.5 or above.
the existing ToolsTalk2 clients are removed.

After upgrade:

Install the new ToolsTalk2 2.21 clients.