diff --git a/controller/config.go b/controller/config.go
index 6b984e69..5ac9533e 100644
--- a/controller/config.go
+++ b/controller/config.go
@@ -6,7 +6,10 @@ import (
 	"github.com/pkg/errors"
 )
 
+const ConfigVersion = 1
+
 type Config struct {
+	V            int
 	Endpoint     *EndpointConfig
 	Proxy        *ProxyConfig
 	Email        *EmailConfig
@@ -61,5 +64,8 @@ func LoadConfig(path string) (*Config, error) {
 	if err := cf.BindYaml(cfg, path, cf.DefaultOptions()); err != nil {
 		return nil, errors.Wrapf(err, "error loading controller config '%v'", path)
 	}
+	if cfg.V != ConfigVersion {
+		return nil, errors.Errorf("expecting configuration version '%v', your configuration is version '%v'; please see zrok.io for changelog and configuration documentation", ConfigVersion, cfg.V)
+	}
 	return cfg, nil
 }
diff --git a/etc/ctrl.yml b/etc/ctrl.yml
index ec1a4ec4..842776a6 100644
--- a/etc/ctrl.yml
+++ b/etc/ctrl.yml
@@ -4,6 +4,8 @@
 #   /___|_|  \___/|_|\_\
 # controller configuration
 
+v:                  1
+
 endpoint:
   host:             0.0.0.0
   port:             18080