With the release of Tal'Dorei Campaign Setting Reborn (TSCR) fast approaching, I think it'd be good to have some guidelines for dealing with any potential contradictory information and retcons of information from the original Tal'Dorei Campaign Setting (TCS).
Note that these are only suggestions and not hard and fast rules, and I'm open to discussion and comentary!
1: Remember that TCS takes place before TSCR
Because TSC takes place in 812 PD and TSCR takes place in 836, some information has changed in the intervening years, such as the members of the Tal'Dorei Council. Keep the information cited from TSC and make note of the year, and add any new information as needed.
Specifically I want to address the populations of cities, which no doubt have changed in the intervening years, just look at the new official map of Whitestone and see how much it's grown! For the infobox, add the new population from TCSR and note the year, replacing the old population so as to keep the most up to date info in the box. Then keep the original TSC population noted in the "Demographics" section under "Society" on the page, with note for how the population has changed.
2: TCS is still a valid source
If any information in TCS is corroborated, or at the very least not directly contradicted in TSCR, there is no need to change the references across the site to point to the same information in the new book. Likewise if for some reason any information is present in TCS and is not present or contradicted in TCSR, it can remain.
3: TCSR takes precedent over TCS
It has been noted by the writers that some changes have been made to the lore, most visibly the addition of some new rivers between Torian Forest and Emon on the new updated map by Andy Law. In the case of retcons and contradictory information, TCSR is considered to be the new canon, and any information should be updated.
4: Old canon can remain under "Behind the scenes"
Mention of what existed before such retcons can remain on the page, listed under the section "Behind the scenes". Make note of what the canon was before and what was changed, and why if possible.
5: The events of Critical Role takes precedent in the case of continuity errors
This has happened before in the official setting guide books. In the Explorer's Guide to Wildemount, the Chroma Conclave are stated to have attacked Draconia in 815 PD, when those events actually occurred in Critical Role in late 810 PD, corroborated by the official Time Line stating that Campaign One took place between 810 and 812 PD.
Should anything in TCSR somehow directly contradict the events of Critical Role, make note of the continuity error under "Behind the scenes".