diff --git a/NEWS b/NEWS
index 2c32d59d..b434fddf 100644
--- a/NEWS
+++ b/NEWS
@@ -20,7 +20,7 @@ Bugs corrected:
 
 Backward-incompatible changes:
 
-    * Support for Docker API < 2.0 is deprecated (Docker plugins)
+    * Minimum supported Docker API version is now 1.21 (Docker plugins)
     * Support for InfluxDB < 0.9 is deprecated (InfluxDB exporter)
 
 News command line options:
diff --git a/optional-requirements.txt b/optional-requirements.txt
index b6977703..93f199ca 100644
--- a/optional-requirements.txt
+++ b/optional-requirements.txt
@@ -2,7 +2,7 @@ bernhard
 bottle
 cassandra-driver
 couchdb
-docker
+docker>=2.0.0
 elasticsearch
 influxdb
 kafka-python