IIRC, the HP Replacement Pages mainly inserted new stuff, but I hope nothing was missed (besides the footnote mentioned below) and that those sections that are not new now have any old existing errata included - those rules should be denoted by a black bullet.
Regarding errata applying the to HP Replacement Pages, I have found two items - both from ASL Journal 11.
The rules covered by the HP Replacement Pages are:
A24.61 - A26.4
B32.32 - B36.6
D15. - D17.5
The errata that applies to these are:
B27.6 and Chapter B Footnotes: change existing footnote “3a”
to “3B” and add new Chapter B footnote “3a. 10.1 HiLLS: In addition
to having visible Crest Lines beneath some terrain, newer
boards are much better at depicting where Crest Lines actually are
by using gaps in the terrain. In many areas of these boards, most
players will be able to agree on where the Crest Lines actually are
underneath the other terrain of grain, brush, woods, or buildings
even without visible Crest Lines. When players can so agree, we encourage
them to use the actual Crest Lines to determine LOS.”.
(This errata from JOURNAL 10 also applies to page B43 provided
in Hakkaa Päälle!)
D16.12: line 3, after “orchard-roads” add “and brush-roads”.
The footnote errata is from ASL Journal 10, and it was missed when the HP pages were created.