The Terraria server we play on just got updated, so now I can't join it. The people I play with got their update immediately via Steam and have already resumed gaming, but there is no update available on GoG yet. How long does that usually take? Minutes? Hours? Days?

It normally takes a few hours. IF not by late night, tomorrow the update should be available.

Thanks, I'll try again tomorrow.

from Judas on the Terraria 1.3 announcement thread:
"It depends on where a dev is sometimes because if they are on the other side of the world in terms of time zones then they could be uploading a patch or update when we are all asleep so we make sure to get the patch out the next day barring any technical issues, of course :)

In any case, just checked my email and the Terraria devs have informed us that they have uploaded an update for us so hopefully we'll get everyone updated as soon as possible :)"

http://www.gog.com/forum/general/content_update_terraria_13_89ddd/post123