diff --git a/include/wlr/types/wlr_output_management_v1.h b/include/wlr/types/wlr_output_management_v1.h
index 2835a5924..723696e9b 100644
--- a/include/wlr/types/wlr_output_management_v1.h
+++ b/include/wlr/types/wlr_output_management_v1.h
@@ -55,7 +55,7 @@ struct wlr_output_head_v1_state {
 		int32_t width, height;
 		int32_t refresh;
 	} custom_mode;
-	int32_t x, y;
+	int32_t x, y, width, height;
 	enum wl_output_transform transform;
 	float scale;
 	bool adaptive_sync_enabled;
diff --git a/protocol/wlr-output-management-unstable-v1.xml b/protocol/wlr-output-management-unstable-v1.xml
index 541284a8c..34e9dda5f 100644
--- a/protocol/wlr-output-management-unstable-v1.xml
+++ b/protocol/wlr-output-management-unstable-v1.xml
@@ -39,7 +39,7 @@
     interface version number is reset.
   </description>
 
-  <interface name="zwlr_output_manager_v1" version="4">
+  <interface name="zwlr_output_manager_v1" version="5">
     <description summary="output device configuration manager">
       This interface is a manager that allows reading and writing the current
       output device configuration.
@@ -125,7 +125,7 @@
     </event>
   </interface>
 
-  <interface name="zwlr_output_head_v1" version="4">
+  <interface name="zwlr_output_head_v1" version="5">
     <description summary="output device">
       A head is an output device. The difference between a wl_output object and
       a head is that heads are advertised even if they are turned off. A head
@@ -140,6 +140,11 @@
       Properties sent via this interface are applied atomically via the
       wlr_output_manager.done event. No guarantees are made regarding the order
       in which properties are sent.
+
+      The viewport indicates the logical size taken by the output in the global
+      compositor space. If the viewport aspect ratio doesn't match the current
+      mode aspect ratio, the compositor should letter-box the output with black
+      borders.
     </description>
 
     <event name="name">
@@ -229,7 +234,7 @@
 
     <event name="position">
       <description summary="current position">
-        This events describes the position of the head in the global compositor
+        This event describes the position of the head in the global compositor
         space. It is only sent if the output is enabled.
       </description>
       <arg name="x" type="int"
@@ -250,6 +255,9 @@
       <description summary="current scale">
         This events describes the scale of the head in the global compositor
         space. It is only sent if the output is enabled.
+
+        Starting from version 5, this event is deprecated: the viewport event
+        should be used instead.
       </description>
       <arg name="scale" type="fixed"/>
     </event>
@@ -364,9 +372,20 @@
       </description>
       <arg name="state" type="uint" enum="adaptive_sync_state"/>
     </event>
+
+    <!-- Version 5 additions -->
+
+    <event name="viewport" since="5">
+      <description summary="head viewport">
+        This event describes the size of the head in the global compositor
+        space. It is only sent if the output is enabled.
+      </description>
+      <arg name="width" type="int" summary="logical width"/>
+      <arg name="height" type="int" summary="logical height"/>
+    </event>
   </interface>
 
-  <interface name="zwlr_output_mode_v1" version="3">
+  <interface name="zwlr_output_mode_v1" version="5">
     <description summary="output mode">
       This object describes an output mode.
 
@@ -421,7 +440,7 @@
     </request>
   </interface>
 
-  <interface name="zwlr_output_configuration_v1" version="4">
+  <interface name="zwlr_output_configuration_v1" version="5">
     <description summary="output configuration">
       This object is used by the client to describe a full output configuration.
 
@@ -539,7 +558,7 @@
     </request>
   </interface>
 
-  <interface name="zwlr_output_configuration_head_v1" version="4">
+  <interface name="zwlr_output_configuration_head_v1" version="5">
     <description summary="head configuration">
       This object is used by the client to update a single head's configuration.
 
@@ -554,6 +573,7 @@
       <entry name="invalid_scale" value="5" summary="scale negative or zero"/>
       <entry name="invalid_adaptive_sync_state" value="6" since="4"
         summary="invalid enum value used in the set_adaptive_sync request"/>
+      <entry name="invalid_viewport" value="7" summary="viewport negative or zero"/>
     </enum>
 
     <request name="set_mode">
@@ -594,6 +614,9 @@
     <request name="set_scale">
       <description summary="set the scale">
         This request sets the head's scale.
+
+        Starting from version 5, this request is deprecated: clients should use
+        set_viewport instead.
       </description>
       <arg name="scale" type="fixed"/>
     </request>
@@ -607,5 +630,17 @@
       </description>
       <arg name="state" type="uint" enum="zwlr_output_head_v1.adaptive_sync_state"/>
     </request>
+
+    <!-- Version 5 additions -->
+
+    <request name="set_viewport" since="5">
+      <description summary="set the viewport">
+        This request sets the head's viewport.
+
+        This overrides the set_scale request, if any was sent.
+      </description>
+      <arg name="width" type="int" summary="logical width"/>
+      <arg name="height" type="int" summary="logical height"/>
+    </request>
   </interface>
 </protocol>
diff --git a/types/wlr_output_management_v1.c b/types/wlr_output_management_v1.c
index 910bcbe5e..c92105008 100644
--- a/types/wlr_output_management_v1.c
+++ b/types/wlr_output_management_v1.c
@@ -6,7 +6,7 @@
 #include <wlr/util/log.h>
 #include "wlr-output-management-unstable-v1-protocol.h"
 
-#define OUTPUT_MANAGER_VERSION 4
+#define OUTPUT_MANAGER_VERSION 5
 
 enum {
 	HEAD_STATE_ENABLED = 1 << 0,
@@ -15,11 +15,12 @@ enum {
 	HEAD_STATE_TRANSFORM = 1 << 3,
 	HEAD_STATE_SCALE = 1 << 4,
 	HEAD_STATE_ADAPTIVE_SYNC = 1 << 5,
+	HEAD_STATE_VIEWPORT = 1 << 6,
 };
 
 static const uint32_t HEAD_STATE_ALL = HEAD_STATE_ENABLED | HEAD_STATE_MODE |
 	HEAD_STATE_POSITION | HEAD_STATE_TRANSFORM | HEAD_STATE_SCALE |
-	HEAD_STATE_ADAPTIVE_SYNC;
+	HEAD_STATE_ADAPTIVE_SYNC | HEAD_STATE_VIEWPORT;
 
 static const struct zwlr_output_head_v1_interface head_impl;
 
@@ -162,6 +163,8 @@ struct wlr_output_configuration_head_v1 *
 	config_head->state.scale = output->scale;
 	config_head->state.adaptive_sync_enabled =
 		output->adaptive_sync_status == WLR_OUTPUT_ADAPTIVE_SYNC_ENABLED;
+	config_head->state.width = output->width * output->scale;
+	config_head->state.height = output->height * output->scale;
 	return config_head;
 }
 
@@ -307,6 +310,26 @@ static void config_head_handle_set_adaptive_sync(struct wl_client *client,
 	}
 }
 
+static void config_head_handle_set_viewport(struct wl_client *client,
+		struct wl_resource *config_head_resource,
+		int32_t width, int32_t height) {
+	struct wlr_output_configuration_head_v1 *config_head =
+		config_head_from_resource(config_head_resource);
+	if (config_head == NULL) {
+		return;
+	}
+
+	if (width <= 0 || height <= 0) {
+		wl_resource_post_error(config_head_resource,
+			ZWLR_OUTPUT_CONFIGURATION_HEAD_V1_ERROR_INVALID_VIEWPORT,
+			"invalid viewport");
+		return;
+	}
+
+	config_head->state.width = width;
+	config_head->state.height = height;
+}
+
 static const struct zwlr_output_configuration_head_v1_interface config_head_impl = {
 	.set_mode = config_head_handle_set_mode,
 	.set_custom_mode = config_head_handle_set_custom_mode,
@@ -314,6 +337,7 @@ static const struct zwlr_output_configuration_head_v1_interface config_head_impl
 	.set_transform = config_head_handle_set_transform,
 	.set_scale = config_head_handle_set_scale,
 	.set_adaptive_sync = config_head_handle_set_adaptive_sync,
+	.set_viewport = config_head_handle_set_viewport,
 };
 
 static void config_head_handle_resource_destroy(struct wl_resource *resource) {
@@ -752,6 +776,7 @@ static struct wl_resource *head_send_mode(struct wlr_output_head_v1 *head,
 static void head_send_state(struct wlr_output_head_v1 *head,
 		struct wl_resource *head_resource, uint32_t state) {
 	struct wl_client *client = wl_resource_get_client(head_resource);
+	uint32_t version = wl_resource_get_version(head_resource);
 
 	if (state & HEAD_STATE_ENABLED) {
 		zwlr_output_head_v1_send_enabled(head_resource, head->state.enabled);
@@ -805,8 +830,7 @@ static void head_send_state(struct wlr_output_head_v1 *head,
 	}
 
 	if ((state & HEAD_STATE_ADAPTIVE_SYNC) &&
-			wl_resource_get_version(head_resource) >=
-			ZWLR_OUTPUT_HEAD_V1_ADAPTIVE_SYNC_SINCE_VERSION) {
+			version >= ZWLR_OUTPUT_HEAD_V1_ADAPTIVE_SYNC_SINCE_VERSION) {
 		if (head->state.adaptive_sync_enabled) {
 			zwlr_output_head_v1_send_adaptive_sync(head_resource,
 				ZWLR_OUTPUT_HEAD_V1_ADAPTIVE_SYNC_STATE_ENABLED);
@@ -815,6 +839,12 @@ static void head_send_state(struct wlr_output_head_v1 *head,
 				ZWLR_OUTPUT_HEAD_V1_ADAPTIVE_SYNC_STATE_DISABLED);
 		}
 	}
+
+	if ((state & HEAD_STATE_VIEWPORT) &&
+			version >= ZWLR_OUTPUT_HEAD_V1_VIEWPORT_SINCE_VERSION) {
+		zwlr_output_head_v1_send_viewport(head_resource,
+			head->state.width, head->state.height);
+	}
 }
 
 static void head_handle_resource_destroy(struct wl_resource *resource) {
@@ -911,6 +941,9 @@ static bool manager_update_head(struct wlr_output_manager_v1 *manager,
 	if (current->adaptive_sync_enabled != next->adaptive_sync_enabled) {
 		state |= HEAD_STATE_ADAPTIVE_SYNC;
 	}
+	if (current->width != next->width || current->height != next->height) {
+		state |= HEAD_STATE_VIEWPORT;
+	}
 
 	// If  a mode was added to wlr_output.modes we need to add the new mode
 	// to the wlr_output_head