Here's the changes from the three updates since the the expansion (naturally in chronological order):
Fixed the main cause of sync errors and possibly all sync errors
Fixed repair bot exploits and crashes
Fixed server crashes from tethers
Fixed server crashes from drone missiles
Fixed misplaced extenders bug
Fixed Missile Lock/BCPU/RoboSight/PointDefense targeting on DM/EDM/RACE maps
Fixed excessive logging of IRC messages
Fixed flags getting stuck together
Fixed flag capping to be faster and more reliable
Improved load times slightly
Added more hotkeys to the designer (s=snap to grid, m=mirror, comma and period = rotate, ctrl+n = new)
Added server drain feature
Fixed multiple winners bug in Race mode
Fixed laser exploit in Race mode
Fixed spawn timer for Race mode
Fixed some money exploits
Fixed weird deterministic spawn placement when flight testing
Fixed a null reference bug in the UI
Fixed a localization crash in the UI
Fixed incorrect "no thrusters" warning for Impulse Thrusters
Fixed flares in DM / EDM / Race
Fixed a server and client crash from the Minigun
Added an "Add" hotkey (A Key) in Designer for Stabilizer, Salvo, etc
Added memory for "Show Stolen Ships" option
Improved flares - Strong decoy effect during target acquisition
Improved Winch price
Improved light missile launcher capacity / rail count (6)
Improved the size of the version number (1.33 vs 1.32)
Just some maintenance and gentle balancing.
Fixed data directory bug caused by changing avatars
Fixed drone missile crash
Fixed bug where dialogs had no line breaks
Improved prices of heavy platforms
Improvement: Map change no longer kicks players out of the Designer
Improved the size of the version number (1.33 to 1.34)
The netcode related ones are:
Fixed the main cause of sync errors and possibly all sync errors
Improved load times slightly
Added server drain feature
Not a ground breaking improvement, but solid steady progress. Depending on how long it's been since you've played, there are a bunch of other fixes as well, but there are way too many patch notes for me to list here. In recent 2 vs 2 with excessive packet spamming there was no noticeable lag for me, crazy amounts of light guns will still lag a server, but nobody really uses 30+ lightgun ships anymore (and they are less powerful now as well as being on the boring side of silly).