diff --git a/etc/chrony/chrony.conf b/etc/chrony/chrony.conf
index c20e40e4..1ecccaab 100644
--- a/etc/chrony/chrony.conf
+++ b/etc/chrony/chrony.conf
@@ -1,4 +1,5 @@
 # For some reason Debian doesn't ship this line by default, so it needs to
 # be added by user and after that hopefully not conflict with package
 # manager
+# Requires Chrony 4.0
 confdir /etc/chrony/chrony.d
diff --git a/etc/chrony/chrony.d/nts-servers.conf b/etc/chrony/chrony.d/nts-servers.conf
index 21dfa354..0f3662aa 100644
--- a/etc/chrony/chrony.d/nts-servers.conf
+++ b/etc/chrony/chrony.d/nts-servers.conf
@@ -1,3 +1,5 @@
+# NTS requires Chrony 4.0
+
 # This line should be added if it's not in main chrony.conf
 #ntsdumpdir /var/lib/chrony