diff --git a/internal/configuration/sources/env/openvpnselection.go b/internal/configuration/sources/env/openvpnselection.go
index 07d9196b..788aee1e 100644
--- a/internal/configuration/sources/env/openvpnselection.go
+++ b/internal/configuration/sources/env/openvpnselection.go
@@ -61,16 +61,23 @@ func (r *Reader) readOpenVPNProtocol() (tcp *bool, err error) {
 }
 
 func (r *Reader) readOpenVPNCustomPort() (customPort *uint16, err error) {
-	key := "OPENVPN_PORT"
-	s := os.Getenv(key)
+	const currentKey = "VPN_ENDPOINT_PORT"
+	key := "PORT"
+	s := os.Getenv(key) // Retro-compatibility
 	if s == "" {
-		// Retro-compatibility
-		key = "PORT"
+		key = "OPENVPN_PORT" // Retro-compatibility
 		s = os.Getenv(key)
 		if s == "" {
-			return nil, nil //nolint:nilnil
+			key = currentKey
+			s = os.Getenv(key)
+			if s == "" {
+				return nil, nil //nolint:nilnil
+			}
 		}
-		r.onRetroActive("PORT", "OPENVPN_PORT")
+	}
+
+	if key != currentKey {
+		r.onRetroActive(key, currentKey)
 	}
 
 	customPort = new(uint16)
diff --git a/internal/configuration/sources/env/wireguardselection.go b/internal/configuration/sources/env/wireguardselection.go
index f297e3f4..2e9e101f 100644
--- a/internal/configuration/sources/env/wireguardselection.go
+++ b/internal/configuration/sources/env/wireguardselection.go
@@ -55,16 +55,23 @@ func (r *Reader) readWireguardEndpointIP() (endpointIP net.IP, err error) {
 }
 
 func (r *Reader) readWireguardCustomPort() (customPort *uint16, err error) {
-	key := "WIREGUARD_ENDPOINT_PORT"
+	const currentKey = "VPN_ENDPOINT_PORT"
+	key := "WIREGUARD_PORT" // Retro-compatibility
 	s := os.Getenv(key)
 	if s == "" {
-		// Retro-compatibility
-		key = "WIREGUARD_PORT"
+		key = "WIREGUARD_ENDPOINT_PORT" // Retro-compatibility
 		s = os.Getenv(key)
 		if s == "" {
-			return nil, nil //nolint:nilnil
+			key = currentKey
+			s = os.Getenv(key)
+			if s == "" {
+				return nil, nil //nolint:nilnil
+			}
 		}
-		r.onRetroActive("WIREGUARD_PORT", "WIREGUARD_ENDPOINT_PORT")
+	}
+
+	if key != currentKey {
+		r.onRetroActive(key, currentKey)
 	}
 
 	customPort = new(uint16)
diff --git a/internal/provider/custom/connection.go b/internal/provider/custom/connection.go
index 9327c894..d8a61ba3 100644
--- a/internal/provider/custom/connection.go
+++ b/internal/provider/custom/connection.go
@@ -53,7 +53,7 @@ func getWireguardConnection(selection settings.ServerSelection) (
 	}
 }
 
-// Port found is overridden by custom port set with `PORT` or `WIREGUARD_ENDPOINT_PORT`.
+// Port found is overridden by custom port set with `VPN_ENDPOINT_PORT`.
 func getPort(foundPort uint16, selection settings.ServerSelection) (port uint16) {
 	return utils.GetPort(selection, foundPort, foundPort, foundPort)
 }