Have the same thing since the release of 21w11a. I had a 21w08b server world that I was able to upgrade to 21w11a, but on my 21w05b, if I try to upgrade the server to 21w11a, it says world upgrade arent possible and I can't use the old 21w05b client either, I click the play button and it does nothing.
Guy Provost
Have the same thing since the release of 21w11a. I had a 21w08b server world that I was able to upgrade to 21w11a, but on my 21w05b, if I try to upgrade the server to 21w11a, it says world upgrade arent possible and I can't use the old 21w05b client either, I click the play button and it does nothing.