According to data collected by mobile app performance management firm Crittercism, adoption rates for Lollipop stood at a mere 0.15 percent at the same point following its release.
Android releases have always suffered from a far slower adoption rate that iOS simply because of the difference in the way they are distributed to Android-powered smartphones and tablets.
Apple pushes iOS updates direct to all iPhone and iPad users, while Google can only do this for its own Nexus line of hardware. For everyone else – the majority, given that Nexus devices are unsubsidized and therefore more expensive – the update has to go to the handset maker and then to the carrier. This can mean that it can take months for a new update to reach devices, if at all.
One user wrote of how the Lollipop update had turned their Nexus 7 into "nothing more than a paperweight."
If you haven't upgraded, then you might want to hold off doing so until an update is released. This is especially true if you rely on apps that make use of the Adobe Air technology, which seems to be severely bugged under Lollipop.