Google Analytics Importer - tracking "new" data while still importing "old" data?

Hello everyone,

we want to migrate from Google Analytics to Matomo and eventually have the old GA data and the new Matomo data in the same Matomo site. Let’s say we want to start tracking via Matomo-only on day X. The plan is to:

  1. start a Google Analytics Import which creates a new Matomo site “S”
  2. import “some” historical GA data into “S”, let’s say everything between “X minus 3 months” and “X” (exclusive)
  3. on day X, start tracking into “S” via Matomo
    3.1) in parallel, keep importing “even older” data into “S”, for example between “X minus 2 years” and “X minus 3 months” - I’m planning to use the “Re-import date range” functionality for this (I cannot import more data before day X, because the number of sites that I need to import, the Google quota and the time left won’t allow this).

Is this possible? In particular: What is the consequence of doing this? I’ve skimmed over the discussion in, and there were concerns about imported data being purged by invalidation if you were to import GA data into a site that was also being tracked into.

But I’m not sure if this applies here, since the date ranges are disjoint (importing “old” data, tracking “new” data, with no overlap). Is it maybe a question of “going back” far enough? If for example, once Matomo tracking starts, I only import data from last year and earlier, could that be “safe” maybe?

Thanks for any feedback!