Fixing Max Health Reset on Rejoin
What the Max Health Fix Mod Does
Minecraft has a long-standing bug where the Max Health attribute is ignored when a player joins a world or server. If your maximum health is higher than the default because of equipment or effects, the game resets your health back to the default value on join. For example, wearing a helmet that grants bonus max health and leaving the game with more health than the default will still result in your health being lowered when you return.
Max Health Fix Mod resolves this. It makes the game respect your actual Max Health attribute when you join, so your health value is retained instead of being clamped to the default.
Client and Server Behavior
Installed on the client, the mod fixes the bug in single-player worlds. Installed on the server, it fixes the bug for players on that server. This means you can use it alone for local play, or server-side to correct the issue for everyone connected.