We have mixed feelings about the two-part release, but the announcement did provide a positive message about 1.17 being compatible with old worlds. We expect to upgrade the server initially with the summer release as soon as it drops on PaperMC to get some of the new blocks and mobs. However, we are still unsure on how this new generation, which is expected to be released near the end of the year, will affect newly rendered chunks on the current map. There is still plenty of space and expanding the map a few thousand blocks should be doable.