--- a/NEWS Thu Jan 03 21:15:52 2019 +0100
+++ b/NEWS Thu Jan 03 21:36:58 2019 +0100
@@ -167,7 +167,8 @@
* The command-line tool "isabelle update" uses Isabelle/PIDE in
batch-mode to update theory sources based on semantic markup produced in
Isabelle/ML. Actual updates depend on system options that may be enable
-via "-u OPT" (for "update_OPT"). Sessions are specified as in "isabelle
+via "-u OPT" (for "update_OPT"), see also $ISABELLE_HOME/etc/options
+section "Theory update". Theory sessions are specified as in "isabelle
dump".
* Support for Isabelle command-line tools defined in Isabelle/Scala.