No change in world after updating to 1.17

When I updated my Tlauncher to 1.17 , I opened my main survival world and saw that only the texture of ores had changed and only axolotls and glow squids were to be seen new . I explored for 2 days but I found nothing new at all . Then I tried to do this in another world and there I found all the updates working . Now I see no option other than deleting the world I have been playing in for more than 5 months and start grinding in a new one again . Please give me a solution to this problem .