Can you upgrade a weapon more than once

[Ace-Educator]

And still retain both/all three upgrades? (silencer, extended mag, dmg?)

[Cpt Oblivion]

I only have 5 weapons available to upgrade so far, but from what I've seen there's only one active upgrade (which is to say, an upgrade you can switch on or off) available for each gun. The other upgrades are passive, and can be combined (EG a silencer and an expanded magazine can coexist- for the pistol I'd imagine enabling the damage/noise boost upgrade probably cancels out the silencer- or maybe the silencer reduces but doesn't totally silence that upgrade, but once ulocked the silencer is always on, and the damage boost can be switched on or off at will once it's unlocked)

[Riverstyx]

Yes. Most weapons have two passive upgrades and one toggled upgrade.