Due to the nature of mods, it's impossible to keep compatibility with every patch. The gamedata directory overwrites files stored in the .db files, even the patches. This loading order is dictated by the order in fsgame.ltx. This means it's possible addons will not break when you install patches but your game will be using old files. It's up to the addon creator to unpack the patches and release a compatible addon for the current CoC version.
AO3 and OWR3 will most likely always be compatible and are currently the only TeamEPIC supported addons for Call of Chernobyl. Purely comestic mods (textures/meshes) should always be compatible as well. Because of how easy it is to break a mod install, this is one reason why we chose to make an Auto Updater, which can validate and fix your game files.
Technical Information about Patches:

Patch information will be stored in xpatch_01_*.db files. These are split up intentionally so that patches can be small as possible. For example, if a script or config update was made, it will only be a small 500kb re-download of xpatch_01_config.db.

Main changes:
1) fix agroprom terrain (author LostAlphaRus)
2) fix trucks cemetery ambient (author LostAlphaRus) and level bound (noname author)
3) more Russian audio voices (author zoober)
4) better Pripyat and Radar world map textures (author NatVac)
5) free tier 3 upgrade (author VantuZ)
6) fix initial equipment: mp5 and beretta now with 9x19 ammo, ak74u now with 5.45x39 ammo (Death_KnightRZ) (AO3.xml version fixed too)
7) weapon removed during bandaging, eating and any other actions (Tris)
8) vinca, psy blockade, antidot, radioprotector, vodka and energy drink now have right weight after 1 or more uses
9) all types of medical kits used by no more than two times
10) added missed merc_exo_outfit, monolith_outfit and monolith_scientific_outfit to debug menu
11) military, bandits and duty start without detectors (AO3.xml version fixed too)
12) clear sky, ecologs and mercenary start with simple or advanced detectors (AO3.xml version fixed too)
13) increased damage, range and number of fragments from grenade f1 (original game)
14) removed delay before firing from Mossberg 590 (OWR version)
15) correct range and hit power of the knife (OWR and AO3)
Other items changes:
1) bread
inv_weight 0.3
cost 150
boost_time 30.0
boost_health_restore 0.0002
2) kolbasa
inv_weight 0.4
cost 200
boost_time 40.0
boost_health_restore 0.0002
eat_satiety 0.8
3) conserva
inv_weight 0.5
cost 250
boost_time 50.0
boost_health_restore 0.0002
4) vodka
inv_weight 0.9
max_uses 5
boost_time 120.0
boost_radiation_restore 0.001
5) energy_drink
inv_weight 0.3
max_uses 3
6) antirad
inv_weight 0.01
7) drug_booster
inv_weight 0.1
8) drug_coagulant
boost_time 50.0
boost_bleeding_restore 0.003
9) drug_antidot
boost_time 100.0
10) drug_radioprotector
boost_time 150.0