Wait a minute, you can still update a disk-based version of Steam from 2004 to the current release

pcgamer.com:

Back in 2020, YouTuber and Portal speedrunner nicl83(opens in new tab) uploaded a video detailing a curious discovery: the version of Steam included on retail DVDs of Half-Life 2 can still be recognized by Valve's servers and updated to the modern client we use today.

Now, there are naturally some caveats here. There's really no practical reason to do this⁠—updating the client will effectively wipe the archival, time capsule version of Steam you just installed, and it is so much quicker and easier to get Steam off the official website.

The process is also, naturally, a huge pain. Nicl83 starts in Windows XP, which they describe as providing the «best results» with initially installing Steam from the Half-Life 2 DVD. From there, a halting, almost arcane series of restarts and failed updates to the client gets nicl83 to the point where it's still talking to Valve's servers, but cannot update any further since Steam dropped XP and Vista support in 2018(opens in new tab).

Nicl83 next has to access a virtual machine of the still-supported Windows 7 from the Windows XP install. After transferring the partially-updated Steam installation to the Windows 7 VM, nicl83 is finally able to update all the way and log into their account from what is still that original install from the 2004 Half-Life 2 DVD, just modified beyond all recognition, Ship of Theseus-style.

Again, purely an exercise to prove that you can, in fact, do this, but it's amazing to me that Valve's infrastructure will still support this absolutely primeval iteration of the client. It's like a long-forgotten interstellar colony getting rediscovered by a civilization that's far outpaced it. This continued compatibility, no matter how tenuous, really stands out to me