-The default configure options have changed, packages need to be adapted
-otherwise udev will be installed in /usr. Example configuration options
-are in INSTALL.
+The 'devtmpfs' filesystem is required now, udev will not create or delete
+device nodes anymore, it only adjusts permissions and ownership of device
+nodes and maintains additional symlinks.
+
+A writable /run directory (ususally tmpfs) is required now for a fully
+functional udev, there is no longer a fallback to /dev/.udev.