Thought 1) Upgrade type: light
using glowstone, glow squid, or any other glowing material to upgrade the pack into a light source

Thought 2) Specific upgrade: squid
Be able to update the squid pack with something, like glowstone or glow squid to make the pack into a light source

Thought 3) New pack: glow squid pack
A more complex pack that includes glow squid to be the same as the old pack. Maybe even grants mining haste for extra underwater fun

TLDR: I miss the squid pack already T.T

Definitely miss the squidpack

since squid backpack requires glowing ink sac, night vision will be restored

Restored squid backpack night vision when entering water, due to glowing ink sac in recipe
Available in 1.20.1, 1.21.1, 1.21.8 latest releases

https://www.curseforge.com/minecraft/mc-mods/travelers-backpack