How to view annotated powerpoint presentations in Ubuntu?
ONLYOFFICE claims to be higly compatible with MS Office formats, and it is released under AGPL. There are many ways to install it in Ubuntu, use your favourite method.
Snap Package
ONLYOFFICE is available as a snap and can be installed with
snap install onlyoffice-desktopeditors
Debian package
A .deb-package is also available.
Flatpak
Use the following commands to install it with Flatpak.
flatpak install flathub org.onlyoffice.desktopeditors
As reported by OP, it is a bit slow to start (this is not a snap only issue, even the .deb package takes a lot of time to start compared to libreoffice), but works.
Disclaimer: I'm not affiliated with ONLYOFFICE in any way.
The answers will not be to your liking:
- Nope.
- They can be viewed with O365’s online version of PowerPoint for “free”, but not as free as you are asking