I can't make sense of GoG's version numbering for games...

So for example -

When I originally got THIEF GOLD, the version I downloaded - the file was called:

setup_thief_gold_2.0.0.46.exe

Then today, I saw there was an update - and downloaded it - and that file name is called:

setup_thief_gold_1.26_nd_(21948).exe

Now... if I wasn't looking at the dates, I'd assume the FIRST file was the newer version because it looks to have a "higher version" number (2.0.0.46 vs 1.26_nd_21948)...

Is there actual logic to their file name systems?

GOG have changed their filename scheme several times.

setup_thief_gold_1.26_nd_(21948).exe follow the latest scheme.

setup_thief_gold_2.0.0.46.exe followed GOG's previous scheme.

I forgot when GOG made this transition, but I think it have happened about 1 year ago.

Adding to what kbnrylaec said, the old versioning was based on the version of GOG's installer and GOG's installer build for that game - so, that was the 2nd version of the installer, and the 46th build of that specific game (which continues through installer upgrades).

When GOG makes a new iteration of their installer setup, every subsequent game uses that installer version, and if GOG had packaged a certain game 23 times for installer v1 before updating it with installer v2, the next build would be 2.0.0.24 (then tested and rebuilt until installer bugs with that game are fixed, so the first v2 package on the website might be 2.0.0.37).

Now, however, GOG seems to use the game's version (which the users have requested for a good while) together with another number (21948) that I have less of an idea of where it comes from. It might be installer v2.1.9, package number 48, but that's just a guess from this specific example.

So yes, there is logic... to an extent.

setup_thief_gold_1.26_nd_(21948).exe
The true game version is "1.26 ND", which showed as 1.26_nd in the filename.
The 21948 is build number, which is shared among different GOG games.
A version number followed by a build number is very common in today's software industry.

The problem is, GOG misuse the build number system, and often do not bump the build number.
For example, many different installers of a single game, oftern share exactly the same filename, but have different filesize and checksum.

Besides, latest Linux installers of GOG have super stupid filenames.
Examples:
shadow_tactics_blades_of_the_shogun_en_2_2_10_f_21297.sh
toonstruck_en_gog_2_20292.sh
the_7th_guest_en_patch_3_21683.sh
strafe_en_1_2_update_25_04_2018_20318.sh
orwell_en_1_2_6771_29757_22332.sh
And there are more...

Yeah, they aren't awfully consistent, and I'd guess there is very much a human factor rather than automation in both file naming and build number updating.

We're of the same mind. I though the older version numbering was much easier. But it's good to know there is... some... kind of logic.

I disliked the old version because there was no tie to the actual game version in the filename. Worse, the website often didn't show the file version but the game version which was super confusing.

Now that they've changed things, I miss the old version - it was much easier to read.

I like the new style because it includes the actual game version, which is the most important.

IMO, instead of the number inside the brackets (which tells us, members, nothing), would be better to include the date when the installer was made.

GOG have a very bad record to type correct date.
They often have date typo in their changelog and/or installers.

There were v1 installers (1.x.x.x)
Then v2 installers (2.x.x.x) -> some still have this scheme
Since Galaxy was introduced they added anotherl value lik ementionned above.

But it's clear more the time passes : more & more installers willl follow the last one.

personnal opinion : they should have foollowed the build of the game plus another set of number for their internal database. Would have helped users.

Last point , yes it's not displayed in the filename, but a tab if you right click on the file downloaded (the first file if a game have more than one)s indicates a digital signature with a timestamp (well i don't know how it's presented under another OS thann Windows)

Yeah - I keep all the versions of the games (especially where originally it was perhaps a DOSBOX installer, then they recently changed to SCUMVM - and my preference far and large, with those games is DOSBOX - so I use the DOSBOX versions)...

But yes. I suppose what would have been a good naming scheme was:

GAMETITLE_VERSIONOFGAME_VERSIONINSATLLER.

But they probably had no idea when they started this that it'd go that in depth with what people wanted.

Windows installers also have super stupid filenames:
setup_tooth_and_tail_a4fbb1b_20180907150957_(23542)-1.bin
setup_tooth_and_tail_a4fbb1b_20180907150957_(23542).exe

The true version should be 1.3.0.0.c.