diff --git a/README.md b/README.md

index 122b725..631f5cb 100644

--- a/README.md

+++ b/README.md

@@ -6,6 +6,17 @@ as an NTP client and/or PTP slave in order to synchronize the system clock with

 NTP servers and/or grandmasters in PTP domains. Supported NTP/PTP

 implementations are chrony, ntp (the reference implementation) and linuxptp.

+Warning

+-------

+

+The role replaces the configuration of the given or detected provider

+service on the managed host. Previous settings will be lost, even if

+they are not specified in the role variables (no attempt is made to

+preserve or merge the previous settings, the configuration files are

+replaced entirely). The only setting which is preserved is the choice

+of provider if `timesync_ntp_provider` is not defined (see the

+description of this variable below).

+

 Role Variables

 --------------