UPDATE: STABLE UPDATE 2017-06-22 fixes this problem. Noted here in case it helps anyone else getting these problems.
A couple of showstoppers for me, unfortunately.
Trying to get photos from my camera using gphoto2 it throws an error
An error occurred in the io-library ('Unspecified error'): No error description available.
Running it with --debug gets additional info:
0.168012 ptp_usb_getresp usb.c:466: PTP_OC 0x1016 receiving resp failed: PTP Device Prop Not Supported (0x200a)
0.168030 camera_prepare_capture config.c:486: 'ptp_setdevicepropvalue (params, 0xd207, &propval, PTP_DTC_UINT16)' failed: PTP Device Prop Not Supported (0x200a)
0.168052 camera_init library.c:8163: 'camera_prepare_capture (camera, context)' failed: 'Unspecified error' (-1)
More seriously, MariaDB will no longer close down (which causes a machine shutdown to hang). The relevant part of the error log seems to be:
2017-06-20 13:45:46 139896595089152 [Note] InnoDB: Waiting for page_cleaner to finish flushing of buffer pool
170620 13:45:47 [ERROR] mysqld got signal 11 ;
This could be because you hit a bug. It is also possible that this binary
or one of the libraries it was linked against is corrupt, improperly built,
or misconfigured. This error can also be caused by malfunctioning hardware.
To report this bug, see https://mariadb.com/kb/en/reporting-bugs
We will try our best to scrape up some info that will hopefully help
diagnose the problem, but since we have already crashed,
something is definitely wrong and this may fail.
Server version: 10.1.24-MariaDB
It is possible that mysqld could use up to
key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 401589 K bytes of memory
Hope that's ok; if not, decrease some variables in the equation.
Thread pointer: 0x0
Attempting backtrace. You can use the following information to find out
where mysqld died. If you see no messages after this, something went
stack_bottom = 0x0 thread_stack 0x30000
2017-06-20 13:45:47 139896595089152 [Note] InnoDB: Shutdown completed; log sequence number 385037633
It is also possible that this binary or one of the libraries it was linked against is corrupt, improperly built, or misconfigured
feels relevant. Though I'm not sure how to determine which library the problem is in. Interesting though that the gphoto2 error also refers to library problems.
The shutdown hangs at this point and can only be completed with "killall -9 mysqld".
Rebooting into my rescue installation confirms that both work OK before the update.