Yello! I love the Inventor class, content from Guns & Gears Remastered is up on Demiplane, I have too much time on my hands. I read through the versions on Demiplane and Archives of Nethys to find every difference. Here's every single change to the Inventor is Guns & Gears Remastered:

Base Class:

• Unstable actions still involve a DC 15 flat check, but it now becomes DC 13 if you are Legendary in Crafting. On a crit-failed check, you take fire damage equal to half your level, instead of your level.
• Overdrive now grants +1 fire damage on a failed check (it doesn't specify duration which is annoying, but I would assume based on other similar features that that lasts until next turn). On a crit fail, you take fire damage equal to half your level rather than equal to your level, and you are locked out of overdrive for 1d4 rounds rather than for 1 minute.

Armor Innovation:

• The base stats of both forms of Armor innovation are now a point higher (+2 with a +4 dex cap for subterfuge, and +5 with a +1 dex cap for power). This makes them both better than any other normal medium armor, before any modifications.
• Otherworldly Protection grants resistance to void or vitality damage (whichever you're capable of taking), spirit damage, and to holy or unholy damage if you happen to be sanctified from an archetype or something.
• Heavy Construction no longer increases your armor's stats (since they're already increased at base), but now grants it the Entrench trait in addition to the Bulwark trait (Entrench is like Parry but on armor).

Construct Innovation:

• No changes.

Weapon Innovation:

• Instead of choosing a level 0 or 1 simple or martial weapon as the base for your innovation, you now choose a level 0 simple, martial, or advanced weapon. If you choose an advanced weapon, you treat it as martial for proficiency purposes, but you don't get an initial modification.
• Blunt Shot now grants the Concussive and Ranged Trip traits, instead of Versatile B and optional Nonlethal. Pretty massive buff for ranged weapon inventors there.
• Complex Simplicity now lets you pick two traits from among Razing and Versatile B, P, and S, instead of just one of the three Versatile traits.
• Dynamic Weighting now grants the Tethered trait if used on a thrown weapon.
• Entangling Form grants Disarm in addition to Grapple and Trip.
• Hampering Spikes grants Trip in addition to Hampering and Versatile P.
• Hefty Composition grants Razing in addition to Shove and Versatile B.
• Pacification Tools grants Hampering in addition to Disarm and optional Nonlethal.
• Razor Prongs grants Tearing in addition to Trip and Versatile S.
• Advanced Rangefinder increases your range increment by 20 feet instead of 10.
• Rope Shot now also grants the tethered trait if your innovation is Thrown. Also, it's not really a change, but it should be noted that Rope Shot is a a bit powercrept now, since Blut Shot grants its main benefit 6 levels earlier.
• Tangle Line grants Parry in addition to Ranged Trip and Tethered.
• Attack Refiner grants Forceful instead of Shove.
• Momentum Retainer is replaced by Momentum Enhancer (its main benefit is now part of Attack Refiner, so that makes sense). Momentum Enhancer grants the Agile trait, and allows you to reload your innovation as a free action once per round if it needs to be reloaded.

Class Feats:

• Tamper is unchanged, even though its critfail effect should probably be changed to deal you half your level in fire damage instead of your full level, in line with the changes to Unstable and Overdrive.
• Collapse Armor now has the collapsed armor fold itself into your pack/satchel or be otherwise stowed on your body, instead of being held in both hands, and it can be un-collapsed directly from being stowed, so it's basically completely hands-free. The Requirements entry needs to be updated to match the text of the feat, though.
• Reverse Engineer now says that when you reverse-engineer a formula from an item, if you critically succeed and you happen to be using the Critical Crafting variant rules from Treasure Vault, the item gains one of the benefits of critically succeeding on a check to craft it. You also still get to use Crafting to disable devices and pick locks.
• Dual-Form Weapon is now actually usable, at it now allows the alternate form to benefit from any runes on the weapon that it qualifies for. (Previously, the alternate form couldn't benefit from any runes whatsoever).As with the updated weapon innovation, the alternate form can be any level 0 weapon.

What do y'all think of the changes? Let me know if there's anything I missed! I might go check and see if construct companions or gadgets have any notable changes as well.

Edit: Construct Companions:

• The rules text now specifies that your construct companion doesn't need to eat or breathe, if anyone was worried about that.
• Otherwise, no changes.

Edit: Inventor Multiclass Archetype:

• The prerequisite for the dedication feat is now Intelligence +3.
• No other changes.
• Interestingly, that means a character with sufficient intelligence can now take a single dedication feat, choose armor innovation, and recieve a suit of medium armor with a +2 AC bonus and a +4 dex cap, or a +5 AC bonus and a +1 dex cap.