Forge versions 41.0.64 and 41.0.94 for Minecraft 1.19 together bring a large overhaul to rendering along with general renames to many older fields, methods, and classes that were previously based on MCP names. Together, these changes have broken almost all mods written for any older versions of Forge 1.19 or lower.
However, the Forge team has created a tool to aid modders in automatically remapping their mods to be in line with the renames. This tool has been designed with the future in mind. This means you should be able to use it starting from any Minecraft/Forge version (on FG5) on the way to porting to any future Minecraft/Forge versions (1.19+ / 41.0.94+).