Pentaho hasn't shine for strict release calendar. Also some announced features on roadmap never meet or get delayed for eternity (container execution? webspoon? enhanced AEL?).
Anyway we can try to predict anytime soon, my finger crossed for get a stable LTS version.
From Sourceforge - Pentaho from Hitachi Vantara [1]
Pentaho 9.22021-04-17? -- my trendy assumption
Pentaho 9.12020-09-25
Pentaho 9.02020-02-01
Pentaho 8.32019-07-10
Pentaho 8.22018-12-02
Pentaho 8.12018-05-15
Pentaho 8.02017-11-15
On maven tags we can see first branch tag "9.2.0.0-18" was on "Aug 16, 2020" [2], and most recent tag "9.2.0.0-199" was on "Feb 06, 2021" [3] (six months of active develoment so far ¬¬)
Github project [4] showns almost daily tags, something is baking... But unfourtunly there isn't any Release Candidate tag yet :(
So my best bet is for two or three months more since now. Hope i'm wrong and happy release is behind the corner 😁
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[1] https://sourceforge.net/projects/pentaho/files/
[2] https://mvnrepository.com/artifact/pentaho-kettle/kettle-core/9.2.0.0-18
[3] https://mvnrepository.com/artifact/pentaho-kettle/kettle-core/9.2.0.0-199
[4] https://github.com/pentaho/pentaho-kettle/releases