mrkgnao: I'm sorry. I no longer have the willpower to do it once again, for the umpteenth time.
Time4Tea: This is terrible (the situation with offline installers, not your willpower). Could you possibly post a link to an existing thread about this, that lists which games have very outdated offline installers? It seems like a very important thing to have in my favorites.
There isn't one. Not anything even remotely up to date.
The best I can offer you is the output of a MaGog search.
This is the list of GOG games that MaGog thinks
might have differing offline and galaxy installers for Windows:
[url=]http://www.an-ovel.com/cgi-bin/magog.cgi?ver=1102&scp=gdspuriolnc&dsp=iD&ord=&flt=Ddv~owgw~&opt=n[/url]
And this the same for Mac:
[url=]http://www.an-ovel.com/cgi-bin/magog.cgi?ver=1102&scp=gdspuriolnc&dsp=iD&ord=&flt=Ddv~omgm~&opt=n[/url]
No such list for Linux, because there are no such things as linux galaxy installers.
As usual, GOG's forum software messes up the urls, so copy-paste, rather than click.
Notes:
1) GOG's version system is a complete mess, so I had to develop a complex heuristic algorithm to allow MaGog to guesstimate which versions differ. The algorithm is not perfect --- it has both false positives (MaGog thinks they're different, but they're really not) and false negatives (MaGog thinks they're the same (so they're not on the list above), but they're really not). Like I said, it's not perfect, but I've refined the algorithm over many months, and I'm fairly confident it's reasonably good (despite a couple of minor known bugs and despite having many false positives (better safe than sorry)).
2) The links are live links, so if GOG fixes something (e.g. releases a new offline installer that matches the galaxy one), that game will disappear from the output. Similarly, if GOG messes something up (e.g. releases a new galaxy installer without an offline installer), a new game will appear on the list.
3) This is a MaGog output, and since MaGog doesn't cover games added to GOG in the last year, any outdated installers for these games are unknown. You're on your own there.
4) MaGog's version comparison algorithm ignores patches, so if a game has an offline patch that is newer than the offline installer, and together they bring the offline version to match the galaxy one, MaGog will still list such a game. Luckily, nowadays GOG rarely releases standalone patches without also releasing a new full installer, so it's not a big issue (but you still need to weed these out yourself). However, I now notice that two of the games I had listed before (Trine and TW3) do have such a standalone patch, so they are not in fact outdated, assuming you're backing up patches alongside installers.
Sorry, my bad. I'll delete them from my post above.
5) Don't be alarmed by the large number of games listed. It's not as bad as that. Because of GOG's versioning mess, I expect a large number of these will ultimately prove to be false positive. If we ignore games that are outdated only by 1-2 weeks, which GOG might still fix by themselves, I'd guess that only about 40% of the list will prove to be truly outdated. It's still tens of games, but not as bad as it might look at first glance.
What you want to look at is the section called "Latest Versions" under each game. Let's look at a few examples, to explain how to work with this (again, since this is live output, some of the examples may disappear when GOG makes changes).
EXAMPLE #1
===========
13th Doll: A Fan Game of The 7th Guest, The:
Windows, Offline: 1.1.2
Windows, Galaxy: 1.2.0 {2020-05-11}
Mac OS X, Offline: 1.2.0
Mac OS X, Galaxy: 1.2.0 {2020-05-22}
Linux, Offline: 1.1.2
As you can see the Windows installers differ (1.1.2 vs. 1.2.0) and it appears galaxy's is newer. You can always see when the galaxy installer was released (date is YYYY-MM-DD, so 11 May 2020), but the offline installer's date is listed only if I own the game. Since I don't own this game, MaGog doesn't know when the offline installer was released. However, we can be fairly certain that the offline installer is outdated and that GOG has forgotten about it, since the galaxy installer is almost 6 months old. This is what I would call "Galaxy not optional for 5+ months".
As you can also see, in this case, the Mac installers do not differ and are both up to date.
As you can further see, the Linux offline installer is outdated vis-a-vis the windows galaxy installer. If you want, MaGog can generate comparisons between any pair of installers (e.g. Linux offline vs. Windows galaxy, or Linux offline vs. Windows offline). But that's a different story, as it probably requires getting binaries from the developer. Anyhow, just let me know.
EXAMPLE #2
===========
Ancestors Legacy Windows, Offline: 64721
Windows, Galaxy: 64724 {2020-09-25}
Here again, the installers differ, but we can see that the galaxy installers is "only" 1 week old (25 Sep 2020), so there's still some chance that GOG hasn't forgotten about the offline installer and will release it "soon", even without your intervention.
EXAMPLE #3
===========
Carmageddon 2: Carpocalypse Now Windows, Offline: gog-28 {2015-09-16}
Windows, Galaxy: 1.02A {2017-04-05}
This is a game I own, so we can see the offline installer's date. We can see that the galaxy installer is 18 months newer than the offline one. This doesn't automatically mean that the offline installer is outdated. GOG sometimes changes the galaxy installer for technical reasons without actually changing its content, which changes the date. Usually when they do that, they don't change the version number, or they do change it by appending an "a" (this is a very clever scheme, because no other entity on the planet ever changes a version by appending an "a" to it, so it is entirely foolproof). Accordingly, MaGog's algorithm assumes that two versions that differ only by an "a" are the same (not perfect, but reduces a lot of noise). Unfortunately, in this case the two versions (gog-28 vs. 1.02A) are from two different versioning systems, so it's impossible to say if they're the same, which is why MaGog lists this game. There are two ways to know if the versions differ: (a) ask GOG (this requires you to believe in what they say, which might be difficult for some), or (b) install both versions and compare them (this obviously requires galaxy and owning the game).
EXAMPLE #4
===========
Drive on Moscow Windows, Offline: 1.16b
Windows, Galaxy: 1.16 {2019-02-12}
This looks like the offline installer might be newer than the galaxy one. A rare occurence, but not unheard of. Hard to tell without the offline installer's date (missing since I don't own the game).
EXAMPLE #5
==========
Dungeons & Dragons: Dragonshard Windows, Offline: N/A {2013-04-03}
Windows, Galaxy: 1.02.0001 {2017-10-05}
Sometimes GOG doesn't bother to have a version number, in which case MaGog lists it as "N/A". This can happen for either offline or galaxy installers (or both).
EXAMPLE #6
==========
Might and Magic 6-pack Limited Edition Windows, Offline: Swords of Xeen: 1.0 {2019-03-20} *** MaM 1: 1.0 {2019-03-20} *** MaM 2: 1.0 {2019-03-20} *** MaM 3: 1.0 {2019-03-20} *** MaM 4-5: 1.0 {2019-03-20} *** MaM 6: gog-42 {2015-02-26}
Windows, Galaxy: Swords of Xeen: 1.0 {2019-03-14} *** MaM 1: 1.0 {2019-03-14} *** MaM 2: 1.0 {2019-03-14} *** MaM 3: 1.0 {2019-03-14} *** MaM 4-5: 1.0 {2019-03-15} *** MaM 6: N/A {2015-05-14}
Some games have been unbundled by GOG (i.e. one store item, multiple library boxes). MaGog lists all separate library boxes under the same one store entry, separating them with " *** ". In this, you can see that SoX and MaM1/2/3/4-5 are ok, but MaGog lists this because she's not sure about MaM6 (versions differ and galaxy installer is 3 months newer). Again, no way of knowing without either asking GOG or installing both versions.
I guess that's enough for now.
If you (or someone else) are serious about pursing this, I recommend you open a new thread, copy-paste this post of mine, and start contacting GOG about the games that you consider relevant. Let me know if and when you create this thread --- I will follow it, answer questions and offer advice.
Good luck.