As I'm still not terribly comfortable with the merging tools in Pharo, I've tried to be as cautious as possible:
1) check there are no changes against in my image from magritte2 or pier2 repositories.
2) merge with magritte or pier repository - if uncertain check changes over last few months in 2.8 repositories
3) check the merged code for expected differences in the magritte2 or pier2 repositories


Magritte-Model & Magritte-Pharo-Model
Merge was straightforward. examining the differences after merge between the two repositories I noticed:
MACompatibility doesn't exist with most of the methods being moved to GRPlatform. However request:default: has been added in MACompatibility for which there doesn't appear to be a equivalent in GRPlatform Also I couldn't find an equivalent of openWorkspace:titled: in GRPlatform. So I added magritteRequest:default: and magritteOpenWorkspace:title to GRPlatform with Pharo implementations in GRPharoPlatform.

Magritte-Tests
Lots of merge conflicts, but then I realised that I'd only loaded Magritte-Tests-Model and Magritte-Tests-Pharo-Model *not* Magritte-Tests - Suddenly what was being said previously in the list about maintaining version history made sense. I reloaded the tests and tried to merge again. No merge conflicts, only three updated methods.
-all tests pass-

Magritte-Morph
No changes - though I fixed the load error in MAFileMorph>>choose I changed FileList2 -> FileList

Magritte-Seaside & Magritte-Pharo-Seaside
Straightforward merge, didn't spot anything which needed to be changed for cross-platform


Pier
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What's the purpose of the Magritte-Model, Magritte-Seaside and Magritte-Tests packages in the pier2 repository? I used the packages in the magritte2 repository. Hope that was the plan.

Pier-Core - empty package

Pier-Model
lots of changes but only a couple of merge conflicts and a couple of s/asString/greaseString/ and one s/allSubInstancesOf:do:/magritteAllSubInstancesOf:do:/

Pier-Seaside
lots of changes, but again only a couple of merge conflicts and one s/displayString/greaseString/

Pier-Security
only a couple of methods had changed, one merge conflict

Pier-Tests
lots of changes, only one merge conflict
-all tests pass-

I'm about the save the merged code, but when I try I get an Error: HTTP1.1 401 Unauthorized
Does someone need to give me write permissions to http://source.lukas-renggli.ch/magritte2 and http://source.lukas-renggli.ch/pier2

Cheers

Nick