Is the removal of the mesh door the only change?
In my view this is a retrograde step.
The mesh door allowed some other options, like leaving the door open near lakes riddled with sandflies etc.
I also note references to this being three season.
Is is a 3 or 4?

The Rab rep was negligent in not revealing that the Summit Extreme was “split” into two tents:
Summit Mountain Bivi
Single skin, 2 person mountaineering shelter with increased headroom
Weight:2000g/71oz (+1000g/35oz with optional porch)
Colours: Olive, Red
• Highly breathable Exchange Lite™ fabric
• 10000mm laminated nylon waterproof bathtub base
• Internally pitched DAC 8.84mm Aluminium poles
• 2 sealed ‘donut link’ tie in point, located at top and side
• 4 internal pockets
• Mosquito net door
• Glow in the dark zip pullers
• Available with removable porch adding 140cm length for gear storage
size: 2220 x 1200mm base, 1000mm height
Summit Superlite Bivi
Single skin, 2 person lightweight, low profile mountaineering shelter
Weight:1500g/53oz
Colours: Blue, Red
• Highly breathable Exchange Lite™ eVent® fabric
• 10000mm laminated lightweight ripstop nylon waterproof bathtub base
• Internally pitched DAC 8.84mm Aluminium poles
• 1 sealed ‘donut link’ tie in point, located at top
• Rear snow collection drawcord porthole
• 1 internal pocket
• Glow in the dark zip pullers
• Aluminium pegs
size: 2220 x 1200mm base, 700mm height