Nexus 4 end of support
Nexus devices will also receive updates for security issues documented in our Public Nexus Security Bulletins for at least the following periods:

Three years from when the device first became available on the Google Store

Or, 18 months after the device stopped being sold on the Google Store



Source
As Nexus 4 was released on November 13th 2012 it is outside this time frame and will likely not receive many more monthly updates.