Complete list? I will try but no doubt will forget a few things. I'll update/repost if I remember more changes. Also, I have not added what each change is for or does but can do that when I have more time.
Front-end:
• New Process and Tooling for Screen Threaded Assembly.
• Internal pathway tweak for slight cooling improvement
• Better threading mesh on Screen Assembly, less waste during production
Body:
• New interface between Chamber Assembly and Body tTbe
• Added copper strip overlay into threading
• Added Laser welding to PCB support to body interface
• Switched to new machine handled PCB to PCB support solder interface
Front-PCB:
• Complete Board Re-design
• New layout for better power handling and efficiency
• Upgraded Automotive Grade CPU
• Added buck/boost regulation of LEDs for no flicker
• Total 3 LEDs now evenly spaced around the perimeter of PCB
• Increased board Copper Thickness
• Added In-system-programming and testing at the board level
Heater:
• New Generation 6 (io v1.0)
• Lowest draw resistance we have ever made (estimating 35% lower or more than originals)
• Higher power (65w) and..........70w units
• New binning process allows Ti units to get 70w heater units!
• Heater design has been extensively tested and is highly reliable
• New Vacuum chamber process
• Much proprietary stuff I can't get into
Backend:
• New battery contact with self-cleaning prongs
• Increased spring pressure on battery contact
• Backend threading now made from Brass
• Eliminated 5 interfaces of potential power loss over time
• Gold plating added to every internal power transfer surface
• Solder connection between PCB and Spring assembly
• New Gold Plated springs
• New Direct Contact PCB design
• Black plastic Overmolded into Tickmarks and on button side
• New clip cover with Indicator Tick mark also with black plastic overmold
• New Dial rotation mechanics
• Added Kapton disk
• Adjusted button click
• Changed button contact
Back-end PCB:
• Similar re-design to Front-PCB (CPU/Layout/Design)
• Replaced mechanical mounts with alternative connections
• Improved button response
• Improved pathway for charging
• Added In-system-programming and testing at the board level
Charger:
• Add components to have charger start easier/more reliably
• Changed layout for reliability
• Upgraded wire to PCB attachments
• Added full function testing at board level
Software:
• Software overhaul on all 4 microcontrollers (front, Back, Charger1/2)
• Added better power management
• Added new "heater throttling" for higher efficiency
• Support for higher power heaters
• New low power mode when the battery is low
• Faster response to dial input
Testing
• Added 14 new QC checks through the subassembly process
• Added subassembly and PCB cycle testing before final
• New complete unit cycle tester, including mechanical operation of button, Air draw, and external air temp monitoring. Outputs graphed automatically and comparted with standards. Every unit goes though.
• Charger cycle testing