The readme says the pack works up to 1.21.10 but the highest supported version I saw is 63 (1.21.6), if the number in the pack.mcmeta file is right the readme should change and if the readme is right the pack.mcmeta should change. Assuming the readme is correct I don't see any breaking change in 1.21.11 that should affect the pack. Maybe i'm wrong but isn't it just as easy as updating the pack.mcmeta file?
The readme says the pack works up to 1.21.10 but the highest supported version I saw is 63 (1.21.6), if the number in the pack.mcmeta file is right the readme should change and if the readme is right the pack.mcmeta should change. Assuming the readme is correct I don't see any breaking change in 1.21.11 that should affect the pack. Maybe i'm wrong but isn't it just as easy as updating the pack.mcmeta file?