diff --git a/homeassistant/components/unifi/image.py b/homeassistant/components/unifi/image.py
index dc4fb93eded..c3969c21bc4 100644
--- a/homeassistant/components/unifi/image.py
+++ b/homeassistant/components/unifi/image.py
@@ -41,7 +41,7 @@ class UnifiImageEntityDescriptionMixin(Generic[HandlerT, ApiItemT]):
     """Validate and load entities from different UniFi handlers."""
 
     image_fn: Callable[[UniFiController, ApiItemT], bytes]
-    value_fn: Callable[[ApiItemT], str]
+    value_fn: Callable[[ApiItemT], str | None]
 
 
 @dataclass
@@ -99,7 +99,7 @@ class UnifiImageEntity(UnifiEntity[HandlerT, ApiItemT], ImageEntity):
     _attr_content_type = "image/png"
 
     current_image: bytes | None = None
-    previous_value = ""
+    previous_value: str | None = None
 
     def __init__(
         self,
diff --git a/homeassistant/components/unifi/manifest.json b/homeassistant/components/unifi/manifest.json
index c34d1035158..4cc45ddb6b8 100644
--- a/homeassistant/components/unifi/manifest.json
+++ b/homeassistant/components/unifi/manifest.json
@@ -8,7 +8,7 @@
   "iot_class": "local_push",
   "loggers": ["aiounifi"],
   "quality_scale": "platinum",
-  "requirements": ["aiounifi==50"],
+  "requirements": ["aiounifi==51"],
   "ssdp": [
     {
       "manufacturer": "Ubiquiti Networks",
diff --git a/requirements_all.txt b/requirements_all.txt
index 67041b69fa0..250d1a452ef 100644
--- a/requirements_all.txt
+++ b/requirements_all.txt
@@ -360,7 +360,7 @@ aiosyncthing==0.5.1
 aiotractive==0.5.5
 
 # homeassistant.components.unifi
-aiounifi==50
+aiounifi==51
 
 # homeassistant.components.vlc_telnet
 aiovlc==0.1.0
diff --git a/requirements_test_all.txt b/requirements_test_all.txt
index 38022121f85..2b5e7ea5658 100644
--- a/requirements_test_all.txt
+++ b/requirements_test_all.txt
@@ -335,7 +335,7 @@ aiosyncthing==0.5.1
 aiotractive==0.5.5
 
 # homeassistant.components.unifi
-aiounifi==50
+aiounifi==51
 
 # homeassistant.components.vlc_telnet
 aiovlc==0.1.0