I do agree it is silly locking archiving behind a paywall for an actively updating and free game, but you may get in trouble for distributing it yourself, it's technically pirating it even if it was free
Well... technically, you have a point.
It's a tricky situation. On one hand, the game is free, but the old version isn't. There's no anti-piracy protection, yet you can't download old version from the official site.
However, the forum rules don't explicitly prohibit posting links to other sites or sharing old versions of the game. They only mention being good and avoiding spam.
So, technically, I'm not violating any rules :)
But thanks for warning :3