Update checking is provided by Simple Update Checker

This feature simply adds a line of text to the title screen showing the current version of the modpack and any possible updates.

The mod will not automatically update the modpack for you and is configured to not show any popups prompting to update. So except a minimal impact on your client.

The following mods are not yet available for 1.21.4 but will be added in future updates of this modpack:

• ToolTipFix
• DashLoader
• Fast Portals
• TieFix
• Immersive Optimization
• Palladium
• Inventory Control Tweaks
• Achievements Optimizer
• Client Side Noteblocks
• Smooth Scrolling Refurbished
• Enhanced Block Entities
• Mobtimizations - Entity Performance Fixes
• Nvidium
• Fast Quit
• ThreadTweak
• Particle Core
• Shared Resources

The large list of missing mods will not affect your experience as much as it would seem.