DeNA has announced that Chapters 19 to 21 of Pokémon Masters as well as Interlude 3 will be added to the game in an update on November 6th, 2019. In addition, there is a Main Story Support Missions event that gives players rewards for completing certain missions.

Main Story Support Missions:

Mission Period: 10/23/2019 at 11:00 p.m. – 11/6/2019 at 10:59 p.m.
New Main Story Support Missions! Complete missions to get Gems! New limited-time missions are now available! Complete them to get special rewards!

Important:

• All mission completion rewards must be claimed before the end of the mission period.
• The mission period and its content are subject to change without notice.

Source: https://pokemonmasters-game.com/en-US/announcements/Mission_M2_W4

New Training Course Difficulty Levels!

Date/Time Added: 10/23/2019 at 11:00 p.m. New difficulty levels added to training courses!

Areas Included:

• Level-Up Course: (Super Hard)
• Strike Course: (Super Hard)
• Tech Course: (Super Hard)
• Support Course: (Super Hard)

Source: https://pokemonmasters-game.com/en-US/announcements/Story_M2_W4_2