We are tw:DogFooding Tiki4 for all the main *.tikiwiki.org sites.

The big question: "When should I upgrade?"

Tiki3 has been identified as Long Term Support. If you have all the features you need, you can stay with Tiki 3.x for a while.

Otherwise, you should upgrade to Tiki 4.x, which has more features and a better user interface.

Tiki5 is already well underway!