diff --git a/api/facadeversions.go b/api/facadeversions.go
index 16d3ba22b3f..6a534f44e44 100644
--- a/api/facadeversions.go
+++ b/api/facadeversions.go
@@ -127,7 +127,7 @@ var facadeVersions = map[string][]int{
 	"Subnets":                      {5},
 	"Undertaker":                   {1},
 	"UnitAssigner":                 {1},
-	"Uniter":                       {18},
+	"Uniter":                       {18, 19},
 	"Upgrader":                     {1},
 	"UpgradeSeries":                {3},
 	"UpgradeSteps":                 {2},
diff --git a/apiserver/facades/agent/uniter/register.go b/apiserver/facades/agent/uniter/register.go
index 069f2cd777a..a6ed822e6c1 100644
--- a/apiserver/facades/agent/uniter/register.go
+++ b/apiserver/facades/agent/uniter/register.go
@@ -20,10 +20,21 @@ import (
 // Register is called to expose a package of facades onto a given registry.
 func Register(registry facade.FacadeRegistry) {
 	registry.MustRegister("Uniter", 18, func(ctx facade.Context) (facade.Facade, error) {
+		return newUniterAPIv18(ctx)
+	}, reflect.TypeOf((*UniterAPIv18)(nil)))
+	registry.MustRegister("Uniter", 19, func(ctx facade.Context) (facade.Facade, error) {
 		return newUniterAPI(ctx)
 	}, reflect.TypeOf((*UniterAPI)(nil)))
 }
 
+func newUniterAPIv18(context facade.Context) (*UniterAPIv18, error) {
+	api, err := newUniterAPI(context)
+	if err != nil {
+		return nil, errors.Trace(err)
+	}
+	return &UniterAPIv18{*api}, nil
+}
+
 // newUniterAPI creates a new instance of the core Uniter API.
 func newUniterAPI(context facade.Context) (*UniterAPI, error) {
 	authorizer := context.Auth()
diff --git a/apiserver/facades/agent/uniter/uniter.go b/apiserver/facades/agent/uniter/uniter.go
index bcaf7796c3a..34a04e72907 100644
--- a/apiserver/facades/agent/uniter/uniter.go
+++ b/apiserver/facades/agent/uniter/uniter.go
@@ -38,9 +38,6 @@ import (
 
 var logger = loggo.GetLogger("juju.apiserver.uniter")
 
-// TODO (manadart 2020-10-21): Remove the ModelUUID method
-// from the next version of this facade.
-
 // UniterAPI implements the latest version (v18) of the Uniter API.
 type UniterAPI struct {
 	*common.LifeGetter
@@ -81,6 +78,13 @@ type UniterAPI struct {
 	cloudSpecer     cloudspec.CloudSpecer
 }
 
+// UniterAPIv18 Implements version 18 of the uniter API, which includes methods
+// ModelUUID and OpenedApplicationPortRangesByEndpoint that were removed from
+// later versions.
+type UniterAPIv18 struct {
+	UniterAPI
+}
+
 // OpenedMachinePortRangesByEndpoint returns the port ranges opened by each
 // unit on the provided machines grouped by application endpoint.
 func (u *UniterAPI) OpenedMachinePortRangesByEndpoint(args params.Entities) (params.OpenPortRangesByEndpointResults, error) {
@@ -179,7 +183,7 @@ func (u *UniterAPI) OpenedPortRangesByEndpoint() (params.OpenPortRangesByEndpoin
 }
 
 // OpenedApplicationPortRangesByEndpoint returns the port ranges opened by each application.
-func (u *UniterAPI) OpenedApplicationPortRangesByEndpoint(entity params.Entity) (params.ApplicationOpenedPortsResults, error) {
+func (u *UniterAPIv18) OpenedApplicationPortRangesByEndpoint(entity params.Entity) (params.ApplicationOpenedPortsResults, error) {
 	result := params.ApplicationOpenedPortsResults{
 		Results: make([]params.ApplicationOpenedPortsResult, 1),
 	}
@@ -758,8 +762,7 @@ func (u *UniterAPI) SetWorkloadVersion(args params.EntityWorkloadVersions) (para
 // ModelUUID returns the model UUID that this unit resides in.
 // It is implemented here directly as a result of removing it from
 // embedded APIAddresser *without* bumping the facade version.
-// It should be blanked when this facade version is next incremented.
-func (u *UniterAPI) ModelUUID() params.StringResult {
+func (u *UniterAPIv18) ModelUUID() params.StringResult {
 	return params.StringResult{Result: u.m.UUID()}
 }
 
diff --git a/apiserver/facades/agent/uniter/uniter_test.go b/apiserver/facades/agent/uniter/uniter_test.go
index 8d600a46a51..68f09be50ee 100644
--- a/apiserver/facades/agent/uniter/uniter_test.go
+++ b/apiserver/facades/agent/uniter/uniter_test.go
@@ -3739,7 +3739,8 @@ func (s *uniterSuite) TestOpenedApplicationPortRangesByEndpoint(c *gc.C) {
 
 	uniterAPI := s.newUniterAPI(c, st, s.authorizer)
 
-	result, err := uniterAPI.OpenedApplicationPortRangesByEndpoint(arg)
+	api := &uniter.UniterAPIv18{UniterAPI: *uniterAPI}
+	result, err := api.OpenedApplicationPortRangesByEndpoint(arg)
 	c.Assert(err, jc.ErrorIsNil)
 	c.Assert(result, gc.DeepEquals, params.ApplicationOpenedPortsResults{
 		Results: []params.ApplicationOpenedPortsResult{
diff --git a/apiserver/facades/schema.json b/apiserver/facades/schema.json
index e685833c5bc..cf02cdeb4b3 100644
--- a/apiserver/facades/schema.json
+++ b/apiserver/facades/schema.json
@@ -46229,7 +46229,7 @@
     {
         "Name": "Uniter",
         "Description": "UniterAPI implements the latest version (v18) of the Uniter API.",
-        "Version": 18,
+        "Version": 19,
         "AvailableTo": [
             "controller-machine-agent",
             "machine-agent",
@@ -46757,15 +46757,6 @@
                     },
                     "description": "ModelConfig returns the current model's configuration."
                 },
-                "ModelUUID": {
-                    "type": "object",
-                    "properties": {
-                        "Result": {
-                            "$ref": "#/definitions/StringResult"
-                        }
-                    },
-                    "description": "ModelUUID returns the model UUID that this unit resides in.\nIt is implemented here directly as a result of removing it from\nembedded APIAddresser *without* bumping the facade version.\nIt should be blanked when this facade version is next incremented."
-                },
                 "NetworkInfo": {
                     "type": "object",
                     "properties": {
@@ -46778,18 +46769,6 @@
                     },
                     "description": "NetworkInfo returns network interfaces/addresses for specified bindings."
                 },
-                "OpenedApplicationPortRangesByEndpoint": {
-                    "type": "object",
-                    "properties": {
-                        "Params": {
-                            "$ref": "#/definitions/Entity"
-                        },
-                        "Result": {
-                            "$ref": "#/definitions/ApplicationOpenedPortsResults"
-                        }
-                    },
-                    "description": "OpenedApplicationPortRangesByEndpoint returns the port ranges opened by each application."
-                },
                 "OpenedMachinePortRangesByEndpoint": {
                     "type": "object",
                     "properties": {
@@ -47689,58 +47668,6 @@
                         "scope"
                     ]
                 },
-                "ApplicationOpenedPorts": {
-                    "type": "object",
-                    "properties": {
-                        "endpoint": {
-                            "type": "string"
-                        },
-                        "port-ranges": {
-                            "type": "array",
-                            "items": {
-                                "$ref": "#/definitions/PortRange"
-                            }
-                        }
-                    },
-                    "additionalProperties": false,
-                    "required": [
-                        "endpoint",
-                        "port-ranges"
-                    ]
-                },
-                "ApplicationOpenedPortsResult": {
-                    "type": "object",
-                    "properties": {
-                        "application-port-ranges": {
-                            "type": "array",
-                            "items": {
-                                "$ref": "#/definitions/ApplicationOpenedPorts"
-                            }
-                        },
-                        "error": {
-                            "$ref": "#/definitions/Error"
-                        }
-                    },
-                    "additionalProperties": false,
-                    "required": [
-                        "application-port-ranges"
-                    ]
-                },
-                "ApplicationOpenedPortsResults": {
-                    "type": "object",
-                    "properties": {
-                        "results": {
-                            "type": "array",
-                            "items": {
-                                "$ref": "#/definitions/ApplicationOpenedPortsResult"
-                            }
-                        }
-                    },
-                    "additionalProperties": false,
-                    "required": [
-                        "results"
-                    ]
-                },
                 "ApplicationStatusResult": {
                     "type": "object",
                     "properties": {