The site will be set to "read-only" for one hour or less (i.e. addition of new comments & cars will be disabled for that time) for doing a test of MySQL 5 instead of current version 4.
This will be done this evening (CET timezone); I'll add a notice for admins a little before I do that.

Next step (friday if everything goes well) is to switch to the "SQLLarge" option of our hosting company, as the database is becoming to big. Except if a problem occurs, this will be done in few minutes (then again I'll have to set the site to "read-only" for that time).

At first sight, it seems to work well.
I'll wait few time before removing the "read-only" lock, please check that everything displays fine (i.e. no error), report me anything unusual (except the fact that all admin links are disabled, of course )
First advantage of the change: ÖAF is now listed with the other "O" makes, but it is still not at its real place. Büssing is not more accurately sorted.
I suppose that the "ü" & "ö" are not considered as "u" & "o" by the sorting engine of mysql, but rather as separate characters, respectively between u/v & o/p. To have German characters properly listed, I have to set sort to "German" rather than "general" West-Europe. I am not 100% sure that this does not have side-effects on non-German accent characters, so for the moment I'll keep "general".
A solution would be using full unicode: it would allow anything, including East-European characters, and sorting would be better from what I understand in MySQL documentation. But I am not sure that PHP supports that properly, and it would anyway require many changes. So that will be for later.

the right translation for
ä, ü, ö is ae, ue, oe

Indeed. But that is only available with "German2". In "German1" (what I called "German" above) it translates to the same letter without accent.

I started the upgrade for the database (to have a 100 MB limit instead of current 50, as the database is 47 M)
I hope that it will work fine. If it is the case within few minutes maintenance will be finished.

That seems to work fine...

ok on my side

I see no differences so far

So that means that it worked fine
Now that the site is on MySQL 5, I may be able to add some interesting functionalities, like a "See new comments on pages where I posted".

ooooooh, that will be great thanks in advance