If you want to get all the new GTA: Online content, you'll have to upgrade to the current console generation (or be a PC gamer).
Bit of bad news for those of you still gaming on a PS3 or Xbox 360. The latest GTA Online update - Freemode Events - won't be making their way to the last generation consoles. In fact, Rockstar announced today that no further content would be developed for the old consoles, and if you wanted to enjoy the steady stream of free GTA Online updates, you'll have to either upgrade to an Xbox One or PS4, or join the PC Gaming Master Race.
This move has been a long-time coming, however, as Rockstar mentioned back in May that the day old consoles would stop being supported would eventually come:
"As we mentioned previously, we always knew there might be a point where we would reach the technical capacity of what the older generation of consoles can handle as each downloadable update requires additional memory both for assets and for additional scripting. We have continued to optimize the entire game over time in order to squeeze as much memory as we possibly could out of the last-generation hardware and at some point, continuing to add content for those systems could cause the risk of instability to the game overall."
It looks like the Freemode Events update has finally brought about the beginning of the end for last generation. The good news is that Rockstar has no intention to stop supporting GTA Online servers for the old consoles, so while you won't get the new updates, you'll still be able to play the game.