See v4.13.0's changelog for a majority of other changes.

Next release: When it's ready!

Grammar fix for "View your posts" to "View my posts".
Update notifications will only be triggered if you press "Later" in the update dialog or if an automatic startup check says there is an update. Previously the update notification would be triggered before you chose to update when trying to manually, which would cause the notification to stick around instead of just never appearing.
The toolbar will now blend to and from black when entering or exiting the image viewer.
Text colors have been adjusted for Neon and Solarized Dark. The subject color for Tomorrow has been reverted to it's previous color.
Highlight and divider colors have been adjusted for all themes to be darker rather than lighter. Additional test posts have been added to the theme display for a better visualization.
Fixes the blue color in dark themes to be defaulted to red.
#956, fixes an appearance softlock with phone layout mode and swipeable controllers.
Fixes a banding issue caused by a poor default color configuration being used in the image library.