From 25th May 2018 Google allowed you to automatically wipe user-level data from the reporting from before a cut-off date, to better comply with GDPR.

We made the change for Littledata’s account to wipe user-level data after 26 months, and this is what we found when reporting before February 2016.

Reports you can still view before the user data removal

 Audience metrics
Sessions  ✓
Users  X
Bounce rate  ✓
 Audience dimensions
Demographics  X
OS / Browser  X
Location  X
User Type  X
Custom events X