diff --git a/jsoncpp.spec b/jsoncpp.spec
index 2304022..a826d6a 100644
--- a/jsoncpp.spec
+++ b/jsoncpp.spec
@@ -4,6 +4,8 @@
 %global jsondir json
 
 # Avoid accidental so-name bumps.
+# ATTENTION!!!  You need to run a bootstrap build
+# of cmake *BEFORE* bumping the so-name here!
 %global sover 21