Update 24.07.2018: This guide also works for v3.2 -> v4.1. Just keep in mind that the abbreviation SRIA is the same as OSA

Ideally, you'd read this before importing the package.
If you already imported it, undo the changes so you can start fresh (with a working v3.2 version)
This guide was not tested with earler versions, but you may give it a try

1. Backup your project!
2. Backup? 
3. Open the project without having any compile errors (the exact, working version that you backed up, having a working v3.2 version)
4. Exit play mode
5. Disable the cache server temporarily(you can re-enable it after import), if you're using it. This is a good practice generally, from our testing
6. If you imported without disabling the cache server, go to step 3
7. Delete the old SRIA folder (it's under "Assets/SRIA" initially). This will also block script recompilation until we import the new package, which is good to avoid "MissingReference" errors
8. Only now import the new package
9. Fix all compile errors. Most common issues:
    * Imports. Example:
       - using frame8.Logic.Misc.Visual.UI.ScrollRectItemsAdapter;
       + using Com.ForbiddenByte.OSA.Core;
       + using Com.ForbiddenByte.OSA.CustomParams;
	* Changes in override methods. Example:
       + protected override bool IsRecyclable(InboxCellViewsHolder potentiallyRecyclable, int indexOfItemThatWillBecomeVisible, double sizeOfItemThatWillBecomeVisible)
       - protected override bool IsRecyclable(InboxCellViewsHolder potentiallyRecyclable, int indexOfItemThatWillBecomeVisible, float sizeOfItemThatWillBecomeVisible)
10. Open the scene that contains the old adapters
11. If you're using GridAdapter, set the CellPrefab's minHeight or preferredHeight if using vertical scolling (otherwise set the widths).
Alternatively, you can enable UseDefaultItemSizeForCellGroupSize and provide a value for the "Default Item Size" property. This is the height or width of a row/column
12. Run frame8->SRIA->Migrate from 3.2 to 4.0. This will link the old parameters to the new format & disable the ScrollRect, which you can remove thereafter
13. If you see "0 successful migrations" and there are no errors, your custom SRIA Script may be shown as a MissingReference in inspector. Simply re-assign it using the 
unity's Object selector (i.e. the circle to the right of the "MissingReference" label). Then, do step 11. If after that you'll get some errors, 
it means that the parameters didn't preserve their values and you'll have to manually assign at least the Viewport, Content and ItemPrefab. If all works well, modify 
other properties (effects, looping etc.) tot he desired values
14. If you previously used SRIATouchInputModule/SRIAStandardInputModule, you'll get a MissingReference warning on the EventSystem. Simply remove the 
phantom components and add a single StandardInputModule. Or delete the EventSystem and create a new one
15. Get some rest. It's late