> > 1 - Backup 1.0 database
> > 2 - Uninstall 1.0 server
> > 3 - Install 1.5 server
> > 4 - Copy fbclient.dll over gds32.dll in my app directory.
> > 5 - Restore database
>
> I have just noticed that I need to generate a modified version of
> gds32.dll with instclient app.

Or, you can also make sure that the "Legacy support..." option
in the installation wizard is checked.

> But the rest is ok, right?

Don't forget to backup the security database "isc4.gdb" if
you need the Firebird users for the 1.5 installation as well.

I would do it that way.

1 - Backup 1.0 database with using the database owner
2 - Backup the security database isc4.gdb with SYSDBA
3 - Copy any third-party UDFs to a safe place
4 - Uninstall Firebird 1.0. Make sure that gds32.dll
gets removed
5 - Install Firebird 1.5 with the above mentioned
"Legacy support ..." option
6 - Restore the security database to e.g. security_mig.fdb
with SYSDBA/masterkey
7 - Stop the Firebird 1.5 Guardian service
8 - Replace the existing security.fdb with security_mig.fdb
by renaming the restored security database
9 - Copy the backed up UDFs into the %Firebird%\UDF directory
10 - Start the Firebird 1.5 Guardian service
11 - Restore any 1.0 database backup with the database owner
12 - Enjoy Firebird 1.5 ;-)

That was out of my mind, but I guess it's quite complete.

Good luck,
Thomas Steinmaurer
LogManager Serie - Logging/Auditing Suites supporting
InterBase, Firebird, Advantage Database and MS SQL Server
Upscene Productions
http://www.upscene.com