The producer of Pokémon Masters Yu Sasaki posted an open letter about the game on the Pokémon Master's official website. The letter addresses the upcoming changes to the game.

A Message from the Pokémon Masters EX Team (Vol. 53)

Greetings, Trainers.
We’re the producers of Pokémon Masters EX, Yu Sasaki and Tetsuya Iguchi, here with a new message for you. Today, we’ll focus on details about events beginning around the end of October and the new Sync Pairs that will debut.

App Update for Late October - The Mysterious Stones Chapter Is Coming!

This might seem out of the blue, but have you been able to get any of those Mysterious Stone items that started appearing on Pasio around a month ago?

Mysterious Stones have recently been found across Pasio and have a glow similar to that of Sync Stones. Professor Bellis, the leading Sync Stone researcher, has taken a great interest in them and is analyzing them.

The story of these Mysterious Stones will begin soon! Details are coming in the announcement scheduled for October 31, 2023, so stay tuned.

A New Guest Arrives in the Trainer Lodge

Starting October 31, 2023, you’ll be able to invite Gladion as a Guest to the Trainer Lodge! To invite Gladion, you’ll need to team up with Gladion & Silvally first.
You can team up with Gladion & Silvally from various Sync Pair Scouts, so be sure to invite him once you’ve teamed up with this Sync Pair.

Other Updates

Starting October 31, 2023, you’ll be able to purchase Gems that come with a present of 50,000 Co-op Sync Orbs. You can purchase up to ten of this product each month, so we hope you give it a look if you're running low on Co-op Sync Orbs.

Story Event Who’s the Best Singer? Is Coming!

Story Event Who’s the Best Singer? will begin on October 30, 2023! In this event’s story, Piers, Roxie, and Ryuki have a jam session on Pasio. The show ended with a bang, but some of the fans got a little too heated up. In response, the three musicians decide to put on a special concert battle for the audience!

Roxie and Piers, who star in the event, will appear as Fair-Exclusive Sync Pairs wearing sygna suits! Also, Ryuki will appear in the Sync Pair Scout starting November 3, 2023.
We hope you look forward to it!

Sygna Suit Roxie & Toxtricity

Sygna Suit Roxie & Toxtricity are a Tech Sync Pair that can utilize both a Poison Zone and Electric Terrain. Their EX Role is Strike!

Their G-Max Stun Shock Max Move can leave all opponents either poisoned or paralyzed. Plus, one of their Passive Skills can turn the field of play’s zone into a Poison Zone the first time they use their Max Move each battle.

They can create Electric Terrain by themselves and also use Overdrive, which is an Electric-type attack that hits all opponents. Additionally, their Frenzied Sludge Wave Buddy Move is a Poison-type attack that hits all opponents and lowers all targets’ Sp. Def by two stat ranks. Even though it’s a Poison-type attack, its power increases 50% when the terrain is Electric Terrain, so if both a Poison Zone and Electric Terrain are active, it becomes a potently powerful attack.

Sygna Suit Piers & Toxtricity

Sygna Suit Piers & Toxtricity are a Strike Sync Pair that can utilize both Electric Terrain and a Poison Zone. Their EX Role is Support!

One of their Passive Skills can create Electric Terrain the first time their attack move is successful each battle, and their The Show Begins! Move can turn the field of play’s zone into a Poison Zone and raise their Sp. Atk and critical-hit rate by two stat ranks.

Their Sorrowful Echoes Overdrive Buddy Move can be activated when weather, terrain, or zone effects are active. It’s an Electric-type attack whose power isn’t lowered even if there are multiple targets. Also, it uses two fewer slots of the Move Gauge when the zone is a Poison Zone and its power increases 20% when the target is affected by a status condition.

Plus, they have the Piercing Blows Passive Skill, making them a Sync Pair that can reliably deal damage against any opponent.

The New Mix Scout Is Coming!

On October 31, 2023, a new type of Sync Pair Scout called the Mix Scout will begin! The Mix Scout has a limit to how many times it can be used in one day and can only be used with Paid Gems. In general, this Sync Pair Scout will remain available, and its lineup will change around every six months.

Unlike other Sync Pair Scouts, when a Mix Scout’s period ends, your Scout Points will get carried over to the next one, which will have a different lineup. There will be a Mix Sync Pair that can only be obtained here, so please check it out.

Red & Venusaur

The first Mix Sync Pair is Red & Venusaur. They’re a Field Sync Pair that can unleash Grass-type attacks against all opponents, and their EX Role is Strike!

Their Giga Frenzy Plant Buddy Move can be activated when the terrain is Grassy Terrain. It’s a Grass-type attack whose power isn’t lowered even if there are multiple targets, and can lower the target’s Sp. Def by two stat ranks.

On top of that, their Kanto Journey Legacy Passive Skill turns their successful attacks into critical hits, except in certain circumstances.

Their Max Overgrowth Max Move can turn the field of play’s terrain into Grassy Terrain, and once they’ve been raised to 6★ EX, they can create Grassy Terrain right before using their Sync Move for the first time each battle.

Their Toughen Up to Win! Move can raise the Defense and Sp. Def of one ally by two stat ranks and apply the Gradual Healing effect to that ally, and they can also use Mini Potion All, making them a Sync Pair that excels defensively.

Battle Updates

As we mentioned in a previous message, tough new battles that surpass the challenge of the high-difficulty battles you’ve played up to now called Ultimate Battle will debut in mid-November. Ultimate Battle is permanent content that will have battles regularly added in the future.

Unlike High Score Events or the Champion Stadium, where you can choose Options to adjust the difficulty of battles by doing things like making your opponents stronger, this content focuses purely on the simple three-on-three battle format with a difficulty that’s on a whole different level from before. These battles will prove difficult to win unless you understand your opponent’s actions, how to build your team and Sync Grid, and know how to time the use of your Moves.

For the debut of this content, Ultimate Battle Anabel’s Flickering Flames will be added! We hope you’ll put your skills to the test and take it on.

Also, in the Champion Stadium that will begin on November 5, 2023, the maximum number of points that you can reach by choosing different Options in Master Mode will be raised to 3,000. Choose your Options wisely and try to take on even more challenging battles!

Other Events and Updates

High Score Event Fire-Type Masters is scheduled to start on November 7, 2023. We’re adjusting event rewards, and making it so that you can get Red Skill Feathers, Pink Skill Feathers, and Blue Skill Feathers, which make it easier for certain additional effects to activate, so we hope you take on this event with your Fire-type Sync Pairs.

Also, the popular Eevee celebration event from last year is scheduled to begin in late November. We’re planning to make it even better than it was last year, so we hope you look forward to it.

What to Expect in the Next Message

Our next message is scheduled for late November. In it, we plan to share information about new Sync Pairs and events for December. We’re always working hard to deliver updates and improvements that make the world of Pokémon Masters EX as fun as possible.

Until next time, thank you for playing Pokémon Masters EX.

Pokémon Masters Producer: Yu Sasaki
Operations Producer: Tetsuya Iguchi

Source: https://pokemonmasters-game.com/en-US/announcements/Other_5090_5W_2