The Scarab Sage retirement is slowly approaching, and details are still being released. The most recent post on the Society blog has some more information:

Thank you to all who posted feedback on the December 13 blog discussing mid-season faction changes. Taking this feedback into consideration, the team decided to not retire the Scarab Sages, but rather to make the faction inactive. All characters currently part of the Scarab Sages may retain their membership in the faction. Mechanically, this allows current faction members to accrue Prestige Points and Fame, buy vanities, and continue to complete faction journal card goals. However, there will be no new faction journal card produced for the faction in Season 10, and scenarios are unlikely to provide ongoing stories focused on the faction. This blends the requests of our player base with how the team sees the storylines progressing for the Society as a whole.

This change also means that with the publication of an updated Pathfinder Society Roleplaying Guild Guide in the coming weeks, characters will no longer be able to join the Scarab Sages faction. If you would like to change your character’s faction from the Scarab Sages to any other faction, you may do so at a cost of 0 Prestige Points. You should perform this change either by August 2nd, 2018 or at the beginning of the next adventure the character plays, whichever occurs last.

This change won’t affect which characters have the ability to qualify for the final Scarab Sage boons, but it will give existing sages extra time to get there.

We’ll update our original blog post on the retirement with this information, as well.