NIFI-9376 Updated Admin Guide removing reference to default password

Signed-off-by: Pierre Villard <pierre.villard.fr@gmail.com>

This closes #5519.
diff --git a/nifi-docs/src/main/asciidoc/administration-guide.adoc b/nifi-docs/src/main/asciidoc/administration-guide.adoc
index 5508b90..516800f 100644
--- a/nifi-docs/src/main/asciidoc/administration-guide.adoc
+++ b/nifi-docs/src/main/asciidoc/administration-guide.adoc
@@ -1782,7 +1782,12 @@
 ** Block Size Factor (r): 8
 ** Parallelization Factor (p): 1
 
-All options require a password (`nifi.sensitive.props.key` value) of *at least 12 characters*. This means the "default" value (if left empty, a hard-coded default is used) will not be sufficient.
+All options require a password (`nifi.sensitive.props.key` value) of *at least 12 characters*.
+
+In new standalone installations of 1.14.0 or later, NiFi generates a random value when `nifi.sensitive.props.key` is
+empty. NiFi writes the generated value to `nifi.properties` and logs a warning.
+
+Clustered installations of NiFi require the same value to be configured on all nodes.
 
 [[encrypt-config_tool]]
 == Encrypted Passwords in Configuration Files