Libre Office 5.3.4.3 used to open RC4 encrypted Power Point presentation, but version 5.3.7 say “Opening of password encrypted Power Point document is not supported” when opening the same .pps LO used to open with version 5.3.4.3?
https://wiki.documentfoundation.org/ReleaseNotes/5.3
The contemporary Microsoft Office default Binary Document encryption “RC4 CryptoAPI Encryption” is now supported (Caolán McNamara, Red Hat, Inc.)