Pokémon GO has been updated to Version 0.131.0 on iOS and Version 0.165.0 on Android. Niantic has posted a detailed release notes for this version with lists of new features, updates and bug fixes.

What’s New in Version 0.165.0 (Android) and 0.131.0 (iOS)

• In this update, we’re excited to announce more changes focusing on Trainer Battles!
• Over the next couple of weeks, you’ll see some changes in Pokémon GO’s various combat systems.
• We’re excited to see the teams you build with these changes, Trainers. Stay tuned, as we’ll be sharing more updates like these in the future. Good luck on the battlefield!

Release notes may be posted before the release is available to all players. Please check your app store for the latest version of Pokémon GO available to you.

Updates

• Pokémon eligible for trade Evolution can now be searched using the search term “tradeevolve”
• Attack and Defense stats changes are now cleared after swapping during combat
• During battle, when two Pokémon use Charged Attacks at the same time, the Pokémon with the higher Attack stat will go first. If two Pokémon have the same Attack stat, a random Pokémon will go first.
• Removed EX Raid-eligible tag on Gyms with already scheduled EX Raids
• Updates to Team Go Rocket Leader Shadow Pokémon encounter logic
• Minor visual and audio updates to the Buddy Adventure feature
• New ways to engage in Trainer Battles

Bug Fixes

• Resolved an issue causing Galaxy S10 devices running Android 10 to crash when entering AR+ mode
• The “Walk together” category under “Total Activities” now updates more frequently
• In-game notifications for when your buddy collects a candy now direct you to the new Buddy Profile page
• Fixed a bug where the “Swap Buddies” button on the Buddy Profile page was incorrectly greyed out
• Fixed an issue where buddy walk distance could display as a negative value The “Total days” counter now accurately tracks total days spent with your buddy on the
• Buddy Profile page
• Feeding berries to a buddy is now possible on a rotated device
• Fixed instances when the Rocket Radar view could be superimposed on the normal Map View
• Fixed an issue where a Team GO Rocket dialogue screen could appear when attempting to exit a Team GO Rocket battle
• Added improvements to the Pokémon GO Plus automatic disconnect function
• Your buddy must now be on the Map to receive a “Battle together” Affection heart, matching the existing description of the activity
• Fixed a bug where Trainers could earn a “Visit a new place” Affection heart by spinning the Photo Disk at a previously visited Gym
• Fixed an issue where a Best Buddy Ribbon would not appear on Buddy Pokémon when first reaching the Best Buddy level

Source: https://niantic.helpshift.com/a/pokemon-go/?s=release-notes-known-issues&f=0-165-release-notes&l=en&p=web