Here is a list of some of the new features on the Gen4. There were some internal changes so this essentially makes this a new handgun and needs DOJ approval - when that will happen is anyone's guess. Also, the RTF2 is part of Gen 3.5. The Gen 4's have the RTF3 - it's not as rough as the RTF2. They also got rid of the slide serrations as too many people complained about the appearance.
Features dual recoil spring which should increase reliability
Features Swappable backstraps
Magazine release swappable between left and right
Old magazines still work, but only when mag release is on left side
Gen4 slide is clearly marked as "Gen4"
Glock will cease sales of the 3rd Generation and RTF models
Features dual recoil spring which should increase reliability
Features Swappable backstraps
Magazine release swappable between left and right
Old magazines still work, but only when mag release is on left side
Gen4 slide is clearly marked as "Gen4"
Glock will cease sales of the 3rd Generation and RTF models

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