(Click here for the patchnotes of the previous ARK: Survival Evolved patch 174.2, and here for the patchnotes of the next patch 174.31)

• Gamma adjustment now disabled on PvP/Hardcore servers (by server-side default). Unofficial Servers can force allow gamma adjustment on PvP/Hardcore with this commandline/INI option:
  EnablePvPGamma=true
• Replenishing times on all resources reduced by 40% (will replenish faster)

These are the changes of ARK: Survival Evolved’s Patch 174.3. If not otherwise indicated, they’re quoted from the relevant Steam Thread.

(Original announcement on Steam)