Features:
+* systemd-sysupdate: add support a "best before" in manifests (ie. SHA256SUMS)
+ files, to detect freshness, and refuse stale sources
+
+* systemd-sysupdate: for each transfer support looking at multiple sources,
+ pick source with newest entry. If multiple sources have the same entry, use
+ first configured source. Usecase: "sideload" components from local dirs,
+ without disabling remote sources.
+
+* systemd-sysupdate: support "revoked" items, which cause the client to
+ downgrade/upgrade
+
* portable services: attach not only unit files to host, but also simple
binaries to a tmpfs path in $PATH.