For ROS Lunar Loggerhead these packages have been changed and provide some form of migration notes or tutorials for users which depend on these packages.
Make sure to consult the ROS Kinetic migrations page if you are coming from Jade or older: kinetic/Migration
Multiple spinners on the same queue
In Kinetic using multiple spinners on the same queue resulted in a warning message already that this behavior is unsupported and only exists for backward compatibility. In Lunar the support for this has finally been removed. Trying to use it will result in an exception now. See ros/ros_comm#988 for more information.
Log file rotation
The way log files are being rotated has been changed to follow the common approach of renaming the existing log files with a number incremented by one and continuing to write to a file with the same name. Before ROS deviated from the way other projects and continued writing to the next file increment (not renaming the old files). See ros/ros_comm#854 for more information.
The rosout.log file now contains the node name to make it easier to read the log file. See ros/ros_comm#912 for more information.
Python Logging configuration
The metapackage robot_model is deprecated in Lunar, and it will not be released to ROS M. The packages within will moved to new repositories and continue to be maintained. Any packages which depend on robot_model should instead depend on the packages contained within the metapackage.