It seems that Google is doing a bit of cleanup in the lead up to Google I/O. Their releases this morning seem aimed at ensuring their fleet of Nexus devices have Android 5.1.1 at the very least available, with Google updating their Nexus Factory Images page with Android 5.1.1 images for the Nexus 4 and 3G/LTE versions of the Nexus 7 2012 & 2013.
The images are now available for the Nexus 4 (Build LMY47V), 3G Nexus 7 2012 (Build LMY47V), LTE Nexus 7 2012 (Build LMY47V) on the Factory images page, as are the Android 5.1.1 Binaries for developers.
If you’re wanting to make sure your tablet and phone are up to date with all the bug fixes, then flashing a factory image over the top is probably recommended.
Source: Nexus Factory Images.