The 765cc Triumph three-cylinder will continue in the Moto2 category for at least another three years. One could also imply this means Triumph isn’t done developing this engine for its road models, too.
Begin press release:

Triumph Motorcycles will continue to provide their record-breaking 765cc triple powerplants as Exclusive Engine Supplier to the FIM Moto2 World Championship for another three seasons, from 2022-2024.
Since the start of the 2019 season, Triumph Motorcycles has provided all of the teams with race-tuned 765cc triples, each of which is based on the class-leading Street Triple RS engine. With developments that allow it to breathe more freely, rev harder and deliver a peak power output of more than 138HP (an increase of over 17% on the production engine). This 765cc triple brought to the category a much-welcomed boost in power, transforming the performance and level of competition.
Following Dorna?s intent to bring the Moto2 series closer to MotoGP, the increase in power and torque, combined with a more advanced electronics package, has provided a more relevant training and development ground, while enhancing the overall racing in its own right.
In the last two years, Moto2 graduates have gone on to take podiums and victories in their first seasons in the premier MotoGP class including 2019 Moto2 World Champion Alex Marquez who took a pair of second places in 2020, and title rival Brad Binder with a victory in 2020 and more recently in Austria 2021. Add...