Niantic has announced some general Trainer Battle bug fixes and updates to attacks to Pokémon GO.

Pokémon GO - Community Note: Attack updates and more

Trainers, In this community note, we’d like to share some info about general Trainer Battle bug fixes and updates to attacks.

Updates to the combat system
We have one last batch of changes to Trainer Battles to set the stage for an exciting upcoming feature.

• Charged Attacks and switching will now be queued and activated at the end of the current Fast Attack and won’t be overridden by any following Fast Attacks.
• Certain visual bugs in battles have been fixed.

Updates to existing attacks in Pokémon GO
There have been updates to the following existing attacks in Pokémon GO.

• Megahorn - This Bug-type Charged Attack now deals more damage.
• Volt Switch - This Electric-type Fast Attack now activates and generates energy more quickly.

Attacks new to Pokémon GO
Certain Pokémon will soon be able to learn attacks that hadn’t yet been seen in Pokémon GO!

• Flying Press - We hear this Fighting-type Charged Attack has cropped up in the world of Pokémon GO! However, we haven’t figured out which Pokémon is able to learn it yet. Stay tuned as we investigate!

Pokémon that can learn more attacks
The following Pokémon will be able to learn attacks they couldn’t before.

• Plusle and Minun: Grass Knot - This Grass-type Charged Attack will help the Cheering Pokémon deal with Ground-type Pokémon that could give them trouble in the Great League.
• Lanturn: Spark - Lanturn didn’t previously have an Electric-type attack that was comparable to its Water-type attacks in power. Spark will help make Lanturn a strong lead and help it counter Azumarill with supereffective damage and hit Altaria with neutral damage.
• Ampharos: Thunder Punch - This Charged Attack will make Ampharos a powerful Electric-type attacker in the Great and Ultra Leagues.
• Masquerain: Bubble Beam - This Water-type Charged Attack will give Masquerain a good coverage attack to counter Fire- and Rock-type Pokémon that could otherwise give this Bug- and Flying-type Pokémon trouble.
• Vespiquen: Fury Cutter and Air Slash - The addition of these Bug- and Flying-type attacks gives Vespiquen a boost in power since these attacks match Vespiquen’s types, making Vespiquen more viable in battle.

Pokémon that can learn old attacks once again
As part of the group of Pokémon to debut with Pokémon GO, some Pokémon originally discovered in Kanto have had their attacks change a lot over time! We’re adding back some of the stronger attacks a few of these Pokémon used to learn back in 2016 to make sure these attacks are accessible to players who have joined since then. We’ll look at bringing back more of these attacks over time.

• Raichu: Thunder Shock
• Magneton: Thunder Shock, Discharge
• Venomoth: Poison Fang
• Haunter: Shadow Ball
• Hypno: Shadow Ball

Source: https://pokemongolive.com/en/post/combatrebalance-jan2020/