If you install from .deb files then much of this work is automated.
-* 4.x -> 4.4
+* 4.x -> 5.0
+
+** Web Confirmation Strings
The syntax of confirmation strings for online registrations has changed and old
ones no longer work. This only affects users who registered before the upgrade
with 'disorder deluser USERNAME' (as an administrative user, for instance as
root on the server) and they can start the registration process again.
+** Handling Of Configuration Changes
+
+There is a new mechanism to ensure that the search database and aliases are
+reconstructed if any options that affect them change. Unfortunately this means
+that the reconstruction step always takes place on upgrade from 4.3 or earlier,
+as those versions don't record sufficient information for the server to tell
+whether it needs to reconstruct or not.
+
+The result will be a log message of the form:
+
+new database parameter string dbparams-0-sha256:61609f3e6395ec8dee317ee216fe2848d70c249d347dd03c6a219441a13dd456 - removing old data
+
+...and a slower rescan on startup. Subsequent restarts should not have this
+problem (unless of course you change a relevant option).
+
+** Deprecation Notices
+
+The player --wait-for-device option is deprecated and will be removed in a
+future version.
+
+The 'lock' option no longer does anything. You must delete it from any
+configuration files that contain it. The full set of deprecated options is:
+ allow
+ gap
+ lock
+ prefsync
+ restrict
+ trust
+
* 3.0 -> 4.x
If you customized any of the templates, you will pretty much have to start from