New Feature #1 to go along the screenshots:
Supply system was rewritten. There is now only a single resupply phase, which occurs after replacements (so that newly added elements have a chance to recieve supplies), and before rail repair. Penalties reducing supply delivered to units should generally follow the manual. Rail capacity is no longer unlimited. Units far away from their HQ will no longer resupply from the same city as that HQ. Isolated units and HQs will now be able to resupply from cities or HQs to which they have access. Units and HQs with no overland connection to rail network, will now specify their local port as source of supply, not a distant city on rail. Vehicle and fuel use will be based on the actual path between unit and its HQ or city (not railhead), excluding the cost of sea hexes and ports (in case of cities supplied over sea). Cities not on rail will be able to draw resources (and return surplus resources) from those on rail. Certain penalties are now applied at city level, not unit level (Axis Rail Supply Modifier, First Winter Supply Modifier). Support units resupply now just like combat units, instead through them. Supply is now moved between cities and units in lbs instead of tons (1 ton=2000 lbs), which prevents smaller units to be in vastly better supply than larger units due to needs rounding. Unit supply detail window and supply information tabs in CR were rewritten to show as much details from the new system as possible.