Beginning with the June 6 nightly, CyanogenMod's cutting-edge builds have been based on Android 4.4.3, including the new dialer app (the only major user-facing change in this 0.0.1 version bump). However, since the new dialer apk made some changes in the way assets (UI elements) are assigned, the dialer will force close if you have a theme applied that hasn't been updated to address the issue.
You themers can address the force close issue by copying the 4.4.3 dimens.xml file over to your themes. As for theming the new dialer, themer Patrick Loth explains it as follows in his Google+ post (you need to join the CyanogenMod Theme Engine Alpha community to see it):
You themers can address the force close issue by copying the 4.4.3 dimens.xml file over to your themes. As for theming the new dialer, themer Patrick Loth explains it as follows in his Google+ post (you need to join the CyanogenMod Theme Engine Alpha community to see it):
Many themes designed for the new Theme Engine have already been updated to address this issue (including Patrick Loth's own themes DarkUI, DarkUI Basic and FireChili themes). You can find more themes developed for the new Theme Chooser in our forums and in CyanogenMod's upcoming Theme Showcase app due to be released on June 16.