For 1.21 to 1.21.11

• Backported SkyGrid 26.2 from Java 25 to Java 21
• Get all new features and improvements from 26.2 for older versions
• One plugin build now supports Paper & Folia 1.21 through 1.21.11
• Fresh installs detect the server version & add the blocks, items, mobs & biomes available in that release
• Newer 1.21 servers also get content from every earlier 1.21 update
• Older servers won't receive content added in later versions
• Existing config files are left unchanged when updating
• Fixed version differences for mooshrooms, snow golems, chains & biome names

Commands haven't changed. Existing servers keep their current settings, while fresh servers get defaults matched to their Minecraft version.