[bugfix] Account.last_status_at is a date, not datetime (#3419)

* [bugfix] Account.last_status_at is a date, not datetime

Fix #3418

* update swagger

15 files changed, 82 insertions, 75 deletions

diff --git a/internal/api/client/admin/accountsgetv2_test.go b/internal/api/client/admin/accountsgetv2_test.go
index 83f394803..64c76cc1a 100644
--- a/internal/api/client/admin/accountsgetv2_test.go
+++ b/internal/api/client/admin/accountsgetv2_test.go
@@ -99,7 +99,7 @@ func (suite *AccountsGetTestSuite) TestAccountsGetFromTop() {
       "followers_count": 1,
       "following_count": 1,
       "statuses_count": 8,
-      "last_status_at": "2021-07-28T08:40:37.000Z",
+      "last_status_at": "2021-07-28",
       "emojis": [],
       "fields": [
         {
@@ -157,7 +157,7 @@ func (suite *AccountsGetTestSuite) TestAccountsGetFromTop() {
       "followers_count": 1,
       "following_count": 1,
       "statuses_count": 4,
-      "last_status_at": "2021-10-20T10:41:37.000Z",
+      "last_status_at": "2021-10-20",
       "emojis": [],
       "fields": [],
       "enable_rss": true,
@@ -258,7 +258,7 @@ func (suite *AccountsGetTestSuite) TestAccountsGetFromTop() {
       "followers_count": 2,
       "following_count": 2,
       "statuses_count": 8,
-      "last_status_at": "2024-01-10T09:24:00.000Z",
+      "last_status_at": "2024-01-10",
       "emojis": [],
       "fields": [],
       "enable_rss": true
@@ -351,7 +351,7 @@ func (suite *AccountsGetTestSuite) TestAccountsGetFromTop() {
       "followers_count": 0,
       "following_count": 0,
       "statuses_count": 1,
-      "last_status_at": "2023-11-02T10:44:25.000Z",
+      "last_status_at": "2023-11-02",
       "emojis": [],
       "fields": []
     }
@@ -396,7 +396,7 @@ func (suite *AccountsGetTestSuite) TestAccountsGetFromTop() {
       "followers_count": 0,
       "following_count": 0,
       "statuses_count": 3,
-      "last_status_at": "2021-09-11T09:40:37.000Z",
+      "last_status_at": "2021-09-11",
       "emojis": [],
       "fields": []
     }
diff --git a/internal/api/client/admin/reportsget_test.go b/internal/api/client/admin/reportsget_test.go
index 5213dd574..e3d0a535d 100644
--- a/internal/api/client/admin/reportsget_test.go
+++ b/internal/api/client/admin/reportsget_test.go
@@ -186,7 +186,7 @@ func (suite *ReportsGetTestSuite) TestReportsGetAll() {
         "followers_count": 0,
         "following_count": 0,
         "statuses_count": 3,
-        "last_status_at": "2021-09-11T09:40:37.000Z",
+        "last_status_at": "2021-09-11",
         "emojis": [],
         "fields": []
       }
@@ -231,7 +231,7 @@ func (suite *ReportsGetTestSuite) TestReportsGetAll() {
         "followers_count": 1,
         "following_count": 1,
         "statuses_count": 8,
-        "last_status_at": "2021-07-28T08:40:37.000Z",
+        "last_status_at": "2021-07-28",
         "emojis": [],
         "fields": [
           {
@@ -289,7 +289,7 @@ func (suite *ReportsGetTestSuite) TestReportsGetAll() {
         "followers_count": 1,
         "following_count": 1,
         "statuses_count": 4,
-        "last_status_at": "2021-10-20T10:41:37.000Z",
+        "last_status_at": "2021-10-20",
         "emojis": [],
         "fields": [],
         "enable_rss": true,
@@ -343,7 +343,7 @@ func (suite *ReportsGetTestSuite) TestReportsGetAll() {
         "followers_count": 1,
         "following_count": 1,
         "statuses_count": 4,
-        "last_status_at": "2021-10-20T10:41:37.000Z",
+        "last_status_at": "2021-10-20",
         "emojis": [],
         "fields": [],
         "enable_rss": true,
@@ -410,7 +410,7 @@ func (suite *ReportsGetTestSuite) TestReportsGetAll() {
         "followers_count": 1,
         "following_count": 1,
         "statuses_count": 8,
-        "last_status_at": "2021-07-28T08:40:37.000Z",
+        "last_status_at": "2021-07-28",
         "emojis": [],
         "fields": [
           {
@@ -468,7 +468,7 @@ func (suite *ReportsGetTestSuite) TestReportsGetAll() {
         "followers_count": 0,
         "following_count": 0,
         "statuses_count": 3,
-        "last_status_at": "2021-09-11T09:40:37.000Z",
+        "last_status_at": "2021-09-11",
         "emojis": [],
         "fields": []
       }
@@ -515,7 +515,7 @@ func (suite *ReportsGetTestSuite) TestReportsGetAll() {
           "followers_count": 0,
           "following_count": 0,
           "statuses_count": 3,
-          "last_status_at": "2021-09-11T09:40:37.000Z",
+          "last_status_at": "2021-09-11",
           "emojis": [],
           "fields": []
         },
@@ -660,7 +660,7 @@ func (suite *ReportsGetTestSuite) TestReportsGetCreatedByAccount() {
         "followers_count": 1,
         "following_count": 1,
         "statuses_count": 8,
-        "last_status_at": "2021-07-28T08:40:37.000Z",
+        "last_status_at": "2021-07-28",
         "emojis": [],
         "fields": [
           {
@@ -718,7 +718,7 @@ func (suite *ReportsGetTestSuite) TestReportsGetCreatedByAccount() {
         "followers_count": 0,
         "following_count": 0,
         "statuses_count": 3,
-        "last_status_at": "2021-09-11T09:40:37.000Z",
+        "last_status_at": "2021-09-11",
         "emojis": [],
         "fields": []
       }
@@ -765,7 +765,7 @@ func (suite *ReportsGetTestSuite) TestReportsGetCreatedByAccount() {
           "followers_count": 0,
           "following_count": 0,
           "statuses_count": 3,
-          "last_status_at": "2021-09-11T09:40:37.000Z",
+          "last_status_at": "2021-09-11",
           "emojis": [],
           "fields": []
         },
@@ -910,7 +910,7 @@ func (suite *ReportsGetTestSuite) TestReportsGetTargetAccount() {
         "followers_count": 1,
         "following_count": 1,
         "statuses_count": 8,
-        "last_status_at": "2021-07-28T08:40:37.000Z",
+        "last_status_at": "2021-07-28",
         "emojis": [],
         "fields": [
           {
@@ -968,7 +968,7 @@ func (suite *ReportsGetTestSuite) TestReportsGetTargetAccount() {
         "followers_count": 0,
         "following_count": 0,
         "statuses_count": 3,
-        "last_status_at": "2021-09-11T09:40:37.000Z",
+        "last_status_at": "2021-09-11",
         "emojis": [],
         "fields": []
       }
@@ -1015,7 +1015,7 @@ func (suite *ReportsGetTestSuite) TestReportsGetTargetAccount() {
           "followers_count": 0,
           "following_count": 0,
           "statuses_count": 3,
-          "last_status_at": "2021-09-11T09:40:37.000Z",
+          "last_status_at": "2021-09-11",
           "emojis": [],
           "fields": []
         },
diff --git a/internal/api/client/followrequests/get_test.go b/internal/api/client/followrequests/get_test.go
index b9b6db7c6..07383a319 100644
--- a/internal/api/client/followrequests/get_test.go
+++ b/internal/api/client/followrequests/get_test.go
@@ -100,7 +100,7 @@ func (suite *GetTestSuite) TestGet() {
     "followers_count": 0,
     "following_count": 0,
     "statuses_count": 1,
-    "last_status_at": "2023-11-02T10:44:25.000Z",
+    "last_status_at": "2023-11-02",
     "emojis": [],
     "fields": []
   }
diff --git a/internal/api/client/instance/instancepatch_test.go b/internal/api/client/instance/instancepatch_test.go
index 8b099984d..e309ff4ca 100644
--- a/internal/api/client/instance/instancepatch_test.go
+++ b/internal/api/client/instance/instancepatch_test.go
@@ -177,7 +177,7 @@ func (suite *InstancePatchTestSuite) TestInstancePatch1() {
     "followers_count": 1,
     "following_count": 1,
     "statuses_count": 4,
-    "last_status_at": "2021-10-20T10:41:37.000Z",
+    "last_status_at": "2021-10-20",
     "emojis": [],
     "fields": [],
     "enable_rss": true,
@@ -317,7 +317,7 @@ func (suite *InstancePatchTestSuite) TestInstancePatch2() {
     "followers_count": 1,
     "following_count": 1,
     "statuses_count": 4,
-    "last_status_at": "2021-10-20T10:41:37.000Z",
+    "last_status_at": "2021-10-20",
     "emojis": [],
     "fields": [],
     "enable_rss": true,
@@ -457,7 +457,7 @@ func (suite *InstancePatchTestSuite) TestInstancePatch3() {
     "followers_count": 1,
     "following_count": 1,
     "statuses_count": 4,
-    "last_status_at": "2021-10-20T10:41:37.000Z",
+    "last_status_at": "2021-10-20",
     "emojis": [],
     "fields": [],
     "enable_rss": true,
@@ -648,7 +648,7 @@ func (suite *InstancePatchTestSuite) TestInstancePatch6() {
     "followers_count": 1,
     "following_count": 1,
     "statuses_count": 4,
-    "last_status_at": "2021-10-20T10:41:37.000Z",
+    "last_status_at": "2021-10-20",
     "emojis": [],
     "fields": [],
     "enable_rss": true,
@@ -814,7 +814,7 @@ func (suite *InstancePatchTestSuite) TestInstancePatch8() {
     "followers_count": 1,
     "following_count": 1,
     "statuses_count": 4,
-    "last_status_at": "2021-10-20T10:41:37.000Z",
+    "last_status_at": "2021-10-20",
     "emojis": [],
     "fields": [],
     "enable_rss": true,
@@ -991,7 +991,7 @@ func (suite *InstancePatchTestSuite) TestInstancePatch9() {
     "followers_count": 1,
     "following_count": 1,
     "statuses_count": 4,
-    "last_status_at": "2021-10-20T10:41:37.000Z",
+    "last_status_at": "2021-10-20",
     "emojis": [],
     "fields": [],
     "enable_rss": true,
diff --git a/internal/api/client/mutes/mutesget_test.go b/internal/api/client/mutes/mutesget_test.go
index 9939174a0..abe5b1135 100644
--- a/internal/api/client/mutes/mutesget_test.go
+++ b/internal/api/client/mutes/mutesget_test.go
@@ -148,7 +148,7 @@ func (suite *MutesTestSuite) TestIndefinitelyMutedAccountSerializesMuteExpiratio
 
 	// Fetch all muted accounts for the logged-in account.
 	// The expected body contains `"mute_expires_at":null`.
-	_, err = suite.getMutedAccounts(http.StatusOK, `[{"id":"01F8MH5ZK5VRH73AKHQM6Y9VNX","username":"foss_satan","acct":"foss_satan@fossbros-anonymous.io","display_name":"big gerald","locked":false,"discoverable":true,"bot":false,"created_at":"2021-09-26T10:52:36.000Z","note":"i post about like, i dunno, stuff, or whatever!!!!","url":"http://fossbros-anonymous.io/@foss_satan","avatar":"","avatar_static":"","header":"http://localhost:8080/assets/default_header.webp","header_static":"http://localhost:8080/assets/default_header.webp","followers_count":0,"following_count":0,"statuses_count":3,"last_status_at":"2021-09-11T09:40:37.000Z","emojis":[],"fields":[],"mute_expires_at":null}]`)
+	_, err = suite.getMutedAccounts(http.StatusOK, `[{"id":"01F8MH5ZK5VRH73AKHQM6Y9VNX","username":"foss_satan","acct":"foss_satan@fossbros-anonymous.io","display_name":"big gerald","locked":false,"discoverable":true,"bot":false,"created_at":"2021-09-26T10:52:36.000Z","note":"i post about like, i dunno, stuff, or whatever!!!!","url":"http://fossbros-anonymous.io/@foss_satan","avatar":"","avatar_static":"","header":"http://localhost:8080/assets/default_header.webp","header_static":"http://localhost:8080/assets/default_header.webp","followers_count":0,"following_count":0,"statuses_count":3,"last_status_at":"2021-09-11","emojis":[],"fields":[],"mute_expires_at":null}]`)
 	if err != nil {
 		suite.FailNow(err.Error())
 	}
diff --git a/internal/api/client/reports/reportget_test.go b/internal/api/client/reports/reportget_test.go
index 6b0cf89e0..a5ed14dcd 100644
--- a/internal/api/client/reports/reportget_test.go
+++ b/internal/api/client/reports/reportget_test.go
@@ -130,7 +130,7 @@ func (suite *ReportGetTestSuite) TestGetReport1() {
     "followers_count": 0,
     "following_count": 0,
     "statuses_count": 3,
-    "last_status_at": "2021-09-11T09:40:37.000Z",
+    "last_status_at": "2021-09-11",
     "emojis": [],
     "fields": []
   }
diff --git a/internal/api/client/reports/reportsget_test.go b/internal/api/client/reports/reportsget_test.go
index 96fcafc22..ccede98ca 100644
--- a/internal/api/client/reports/reportsget_test.go
+++ b/internal/api/client/reports/reportsget_test.go
@@ -156,7 +156,7 @@ func (suite *ReportsGetTestSuite) TestGetReports() {
       "followers_count": 0,
       "following_count": 0,
       "statuses_count": 3,
-      "last_status_at": "2021-09-11T09:40:37.000Z",
+      "last_status_at": "2021-09-11",
       "emojis": [],
       "fields": []
     }
@@ -246,7 +246,7 @@ func (suite *ReportsGetTestSuite) TestGetReports4() {
       "followers_count": 0,
       "following_count": 0,
       "statuses_count": 3,
-      "last_status_at": "2021-09-11T09:40:37.000Z",
+      "last_status_at": "2021-09-11",
       "emojis": [],
       "fields": []
     }
@@ -320,7 +320,7 @@ func (suite *ReportsGetTestSuite) TestGetReports6() {
       "followers_count": 0,
       "following_count": 0,
       "statuses_count": 3,
-      "last_status_at": "2021-09-11T09:40:37.000Z",
+      "last_status_at": "2021-09-11",
       "emojis": [],
       "fields": []
     }
@@ -378,7 +378,7 @@ func (suite *ReportsGetTestSuite) TestGetReports7() {
       "followers_count": 0,
       "following_count": 0,
       "statuses_count": 3,
-      "last_status_at": "2021-09-11T09:40:37.000Z",
+      "last_status_at": "2021-09-11",
       "emojis": [],
       "fields": []
     }
diff --git a/internal/api/client/statuses/statushistory_test.go b/internal/api/client/statuses/statushistory_test.go
index bcbeeba7d..983da241c 100644
--- a/internal/api/client/statuses/statushistory_test.go
+++ b/internal/api/client/statuses/statushistory_test.go
@@ -115,7 +115,7 @@ func (suite *StatusHistoryTestSuite) TestGetHistory() {
       "followers_count": 2,
       "following_count": 2,
       "statuses_count": 8,
-      "last_status_at": "2024-01-10T09:24:00.000Z",
+      "last_status_at": "2024-01-10",
       "emojis": [],
       "fields": [],
       "enable_rss": true
diff --git a/internal/api/client/statuses/statusmute_test.go b/internal/api/client/statuses/statusmute_test.go
index e506f8717..e8b6d80f2 100644
--- a/internal/api/client/statuses/statusmute_test.go
+++ b/internal/api/client/statuses/statusmute_test.go
@@ -133,7 +133,7 @@ func (suite *StatusMuteTestSuite) TestMuteUnmuteStatus() {
     "followers_count": 2,
     "following_count": 2,
     "statuses_count": 8,
-    "last_status_at": "2024-01-10T09:24:00.000Z",
+    "last_status_at": "2024-01-10",
     "emojis": [],
     "fields": [],
     "enable_rss": true
@@ -218,7 +218,7 @@ func (suite *StatusMuteTestSuite) TestMuteUnmuteStatus() {
     "followers_count": 2,
     "following_count": 2,
     "statuses_count": 8,
-    "last_status_at": "2024-01-10T09:24:00.000Z",
+    "last_status_at": "2024-01-10",
     "emojis": [],
     "fields": [],
     "enable_rss": true
diff --git a/internal/api/model/account.go b/internal/api/model/account.go
index d34d7d519..3ad5d5399 100644
--- a/internal/api/model/account.go
+++ b/internal/api/model/account.go
@@ -84,8 +84,8 @@ type Account struct {
 	FollowingCount int `json:"following_count"`
 	// Number of statuses posted by this account, according to our instance.
 	StatusesCount int `json:"statuses_count"`
-	// When the account's most recent status was posted (ISO 8601 Datetime).
-	// example: 2021-07-30T09:20:25+00:00
+	// When the account's most recent status was posted (ISO 8601 Date).
+	// example: 2021-07-30
 	LastStatusAt *string `json:"last_status_at"`
 	// Array of custom emojis used in this account's note or display name.
 	// Empty for blocked accounts.
diff --git a/internal/processing/stream/notification_test.go b/internal/processing/stream/notification_test.go
index 2e83714fa..1f04d5103 100644
--- a/internal/processing/stream/notification_test.go
+++ b/internal/processing/stream/notification_test.go
@@ -79,7 +79,7 @@ func (suite *NotificationTestSuite) TestStreamNotification() {
     "followers_count": 0,
     "following_count": 0,
     "statuses_count": 3,
-    "last_status_at": "2021-09-11T09:40:37.000Z",
+    "last_status_at": "2021-09-11",
     "emojis": [],
     "fields": []
   }
diff --git a/internal/processing/stream/statusupdate_test.go b/internal/processing/stream/statusupdate_test.go
index f6024686b..97e056175 100644
--- a/internal/processing/stream/statusupdate_test.go
+++ b/internal/processing/stream/statusupdate_test.go
@@ -90,7 +90,7 @@ func (suite *StatusUpdateTestSuite) TestStreamNotification() {
     "followers_count": 0,
     "following_count": 0,
     "statuses_count": 3,
-    "last_status_at": "2021-09-11T09:40:37.000Z",
+    "last_status_at": "2021-09-11",
     "emojis": [],
     "fields": []
   },
diff --git a/internal/typeutils/internaltofrontend.go b/internal/typeutils/internaltofrontend.go
index 6bd6d0900..3b94687dc 100644
--- a/internal/typeutils/internaltofrontend.go
+++ b/internal/typeutils/internaltofrontend.go
@@ -259,7 +259,7 @@ func (c *Converter) accountToAPIAccountPublic(ctx context.Context, a *gtsmodel.A
 			if a.Stats.LastStatusAt.IsZero() {
 				return nil
 			}
-			return util.Ptr(util.FormatISO8601(a.Stats.LastStatusAt))
+			return util.Ptr(util.FormatISO8601Date(a.Stats.LastStatusAt))
 		}()
 	)
 
diff --git a/internal/typeutils/internaltofrontend_test.go b/internal/typeutils/internaltofrontend_test.go
index 139d8913a..e0671ed79 100644
--- a/internal/typeutils/internaltofrontend_test.go
+++ b/internal/typeutils/internaltofrontend_test.go
@@ -66,7 +66,7 @@ func (suite *InternalToFrontendTestSuite) TestAccountToFrontend() {
   "followers_count": 2,
   "following_count": 2,
   "statuses_count": 8,
-  "last_status_at": "2024-01-10T09:24:00.000Z",
+  "last_status_at": "2024-01-10",
   "emojis": [],
   "fields": [],
   "enable_rss": true
@@ -116,7 +116,7 @@ func (suite *InternalToFrontendTestSuite) TestAccountToFrontendAliasedAndMoved()
   "followers_count": 2,
   "following_count": 2,
   "statuses_count": 8,
-  "last_status_at": "2024-01-10T09:24:00.000Z",
+  "last_status_at": "2024-01-10",
   "emojis": [],
   "fields": [],
   "source": {
@@ -158,7 +158,7 @@ func (suite *InternalToFrontendTestSuite) TestAccountToFrontendAliasedAndMoved()
     "followers_count": 1,
     "following_count": 1,
     "statuses_count": 8,
-    "last_status_at": "2021-07-28T08:40:37.000Z",
+    "last_status_at": "2021-07-28",
     "emojis": [],
     "fields": [
       {
@@ -211,7 +211,7 @@ func (suite *InternalToFrontendTestSuite) TestAccountToFrontendWithEmojiStruct()
   "followers_count": 2,
   "following_count": 2,
   "statuses_count": 8,
-  "last_status_at": "2024-01-10T09:24:00.000Z",
+  "last_status_at": "2024-01-10",
   "emojis": [
     {
       "shortcode": "rainbow",
@@ -258,7 +258,7 @@ func (suite *InternalToFrontendTestSuite) TestAccountToFrontendWithEmojiIDs() {
   "followers_count": 2,
   "following_count": 2,
   "statuses_count": 8,
-  "last_status_at": "2024-01-10T09:24:00.000Z",
+  "last_status_at": "2024-01-10",
   "emojis": [
     {
       "shortcode": "rainbow",
@@ -301,7 +301,7 @@ func (suite *InternalToFrontendTestSuite) TestAccountToFrontendSensitive() {
   "followers_count": 2,
   "following_count": 2,
   "statuses_count": 8,
-  "last_status_at": "2024-01-10T09:24:00.000Z",
+  "last_status_at": "2024-01-10",
   "emojis": [],
   "fields": [],
   "source": {
@@ -489,7 +489,7 @@ func (suite *InternalToFrontendTestSuite) TestStatusToFrontend() {
     "followers_count": 1,
     "following_count": 1,
     "statuses_count": 4,
-    "last_status_at": "2021-10-20T10:41:37.000Z",
+    "last_status_at": "2021-10-20",
     "emojis": [],
     "fields": [],
     "enable_rss": true,
@@ -666,7 +666,7 @@ func (suite *InternalToFrontendTestSuite) TestWarnFilteredStatusToFrontend() {
     "followers_count": 1,
     "following_count": 1,
     "statuses_count": 4,
-    "last_status_at": "2021-10-20T10:41:37.000Z",
+    "last_status_at": "2021-10-20",
     "emojis": [],
     "fields": [],
     "enable_rss": true,
@@ -853,7 +853,7 @@ func (suite *InternalToFrontendTestSuite) TestWarnFilteredBoostToFrontend() {
       "followers_count": 2,
       "following_count": 2,
       "statuses_count": 8,
-      "last_status_at": "2024-01-10T09:24:00.000Z",
+      "last_status_at": "2024-01-10",
       "emojis": [],
       "fields": [],
       "enable_rss": true
@@ -980,7 +980,7 @@ func (suite *InternalToFrontendTestSuite) TestWarnFilteredBoostToFrontend() {
     "followers_count": 1,
     "following_count": 1,
     "statuses_count": 4,
-    "last_status_at": "2021-10-20T10:41:37.000Z",
+    "last_status_at": "2021-10-20",
     "emojis": [],
     "fields": [],
     "enable_rss": true,
@@ -1235,7 +1235,7 @@ func (suite *InternalToFrontendTestSuite) TestStatusToFrontendUnknownAttachments
     "followers_count": 0,
     "following_count": 0,
     "statuses_count": 1,
-    "last_status_at": "2023-11-02T10:44:25.000Z",
+    "last_status_at": "2023-11-02",
     "emojis": [],
     "fields": []
   },
@@ -1398,7 +1398,7 @@ func (suite *InternalToFrontendTestSuite) TestStatusToWebStatus() {
     "followers_count": 0,
     "following_count": 0,
     "statuses_count": 1,
-    "last_status_at": "2023-11-02T10:44:25.000Z",
+    "last_status_at": "2023-11-02",
     "emojis": [],
     "fields": []
   },
@@ -1530,7 +1530,7 @@ func (suite *InternalToFrontendTestSuite) TestStatusToFrontendUnknownLanguage()
     "followers_count": 1,
     "following_count": 1,
     "statuses_count": 4,
-    "last_status_at": "2021-10-20T10:41:37.000Z",
+    "last_status_at": "2021-10-20",
     "emojis": [],
     "fields": [],
     "enable_rss": true,
@@ -1674,7 +1674,7 @@ func (suite *InternalToFrontendTestSuite) TestStatusToFrontendPartialInteraction
     "followers_count": 2,
     "following_count": 2,
     "statuses_count": 8,
-    "last_status_at": "2024-01-10T09:24:00.000Z",
+    "last_status_at": "2024-01-10",
     "emojis": [],
     "fields": [],
     "enable_rss": true
@@ -1780,7 +1780,7 @@ func (suite *InternalToFrontendTestSuite) TestStatusToAPIStatusPendingApproval()
     "followers_count": 1,
     "following_count": 1,
     "statuses_count": 4,
-    "last_status_at": "2021-10-20T10:41:37.000Z",
+    "last_status_at": "2021-10-20",
     "emojis": [],
     "fields": [],
     "enable_rss": true,
@@ -1990,7 +1990,7 @@ func (suite *InternalToFrontendTestSuite) TestInstanceV1ToFrontend() {
     "followers_count": 1,
     "following_count": 1,
     "statuses_count": 4,
-    "last_status_at": "2021-10-20T10:41:37.000Z",
+    "last_status_at": "2021-10-20",
     "emojis": [],
     "fields": [],
     "enable_rss": true,
@@ -2130,7 +2130,7 @@ func (suite *InternalToFrontendTestSuite) TestInstanceV2ToFrontend() {
       "followers_count": 1,
       "following_count": 1,
       "statuses_count": 4,
-      "last_status_at": "2021-10-20T10:41:37.000Z",
+      "last_status_at": "2021-10-20",
       "emojis": [],
       "fields": [],
       "enable_rss": true,
@@ -2250,7 +2250,7 @@ func (suite *InternalToFrontendTestSuite) TestReportToFrontend1() {
     "followers_count": 0,
     "following_count": 0,
     "statuses_count": 3,
-    "last_status_at": "2021-09-11T09:40:37.000Z",
+    "last_status_at": "2021-09-11",
     "emojis": [],
     "fields": []
   }
@@ -2293,7 +2293,7 @@ func (suite *InternalToFrontendTestSuite) TestReportToFrontend2() {
     "followers_count": 1,
     "following_count": 1,
     "statuses_count": 8,
-    "last_status_at": "2021-07-28T08:40:37.000Z",
+    "last_status_at": "2021-07-28",
     "emojis": [],
     "fields": [
       {
@@ -2369,7 +2369,7 @@ func (suite *InternalToFrontendTestSuite) TestAdminReportToFrontend1() {
       "followers_count": 0,
       "following_count": 0,
       "statuses_count": 3,
-      "last_status_at": "2021-09-11T09:40:37.000Z",
+      "last_status_at": "2021-09-11",
       "emojis": [],
       "fields": []
     }
@@ -2414,7 +2414,7 @@ func (suite *InternalToFrontendTestSuite) TestAdminReportToFrontend1() {
       "followers_count": 1,
       "following_count": 1,
       "statuses_count": 8,
-      "last_status_at": "2021-07-28T08:40:37.000Z",
+      "last_status_at": "2021-07-28",
       "emojis": [],
       "fields": [
         {
@@ -2472,7 +2472,7 @@ func (suite *InternalToFrontendTestSuite) TestAdminReportToFrontend1() {
       "followers_count": 1,
       "following_count": 1,
       "statuses_count": 4,
-      "last_status_at": "2021-10-20T10:41:37.000Z",
+      "last_status_at": "2021-10-20",
       "emojis": [],
       "fields": [],
       "enable_rss": true,
@@ -2526,7 +2526,7 @@ func (suite *InternalToFrontendTestSuite) TestAdminReportToFrontend1() {
       "followers_count": 1,
       "following_count": 1,
       "statuses_count": 4,
-      "last_status_at": "2021-10-20T10:41:37.000Z",
+      "last_status_at": "2021-10-20",
       "emojis": [],
       "fields": [],
       "enable_rss": true,
@@ -2603,7 +2603,7 @@ func (suite *InternalToFrontendTestSuite) TestAdminReportToFrontend2() {
       "followers_count": 1,
       "following_count": 1,
       "statuses_count": 8,
-      "last_status_at": "2021-07-28T08:40:37.000Z",
+      "last_status_at": "2021-07-28",
       "emojis": [],
       "fields": [
         {
@@ -2661,7 +2661,7 @@ func (suite *InternalToFrontendTestSuite) TestAdminReportToFrontend2() {
       "followers_count": 0,
       "following_count": 0,
       "statuses_count": 3,
-      "last_status_at": "2021-09-11T09:40:37.000Z",
+      "last_status_at": "2021-09-11",
       "emojis": [],
       "fields": []
     }
@@ -2708,7 +2708,7 @@ func (suite *InternalToFrontendTestSuite) TestAdminReportToFrontend2() {
         "followers_count": 0,
         "following_count": 0,
         "statuses_count": 3,
-        "last_status_at": "2021-09-11T09:40:37.000Z",
+        "last_status_at": "2021-09-11",
         "emojis": [],
         "fields": []
       },
@@ -2866,7 +2866,7 @@ func (suite *InternalToFrontendTestSuite) TestAdminReportToFrontendSuspendedLoca
       "followers_count": 0,
       "following_count": 0,
       "statuses_count": 3,
-      "last_status_at": "2021-09-11T09:40:37.000Z",
+      "last_status_at": "2021-09-11",
       "emojis": [],
       "fields": []
     }
@@ -2958,7 +2958,7 @@ func (suite *InternalToFrontendTestSuite) TestAdminReportToFrontendSuspendedLoca
       "followers_count": 1,
       "following_count": 1,
       "statuses_count": 4,
-      "last_status_at": "2021-10-20T10:41:37.000Z",
+      "last_status_at": "2021-10-20",
       "emojis": [],
       "fields": [],
       "enable_rss": true,
@@ -3012,7 +3012,7 @@ func (suite *InternalToFrontendTestSuite) TestAdminReportToFrontendSuspendedLoca
       "followers_count": 1,
       "following_count": 1,
       "statuses_count": 4,
-      "last_status_at": "2021-10-20T10:41:37.000Z",
+      "last_status_at": "2021-10-20",
       "emojis": [],
       "fields": [],
       "enable_rss": true,
@@ -3158,7 +3158,7 @@ func (suite *InternalToFrontendTestSuite) TestIntReqToAPI() {
     "followers_count": 1,
     "following_count": 1,
     "statuses_count": 4,
-    "last_status_at": "2021-10-20T10:41:37.000Z",
+    "last_status_at": "2021-10-20",
     "emojis": [],
     "fields": [],
     "enable_rss": true,
@@ -3213,7 +3213,7 @@ func (suite *InternalToFrontendTestSuite) TestIntReqToAPI() {
       "followers_count": 1,
       "following_count": 1,
       "statuses_count": 8,
-      "last_status_at": "2021-07-28T08:40:37.000Z",
+      "last_status_at": "2021-07-28",
       "emojis": [],
       "fields": [
         {
@@ -3305,7 +3305,7 @@ func (suite *InternalToFrontendTestSuite) TestIntReqToAPI() {
       "followers_count": 1,
       "following_count": 1,
       "statuses_count": 4,
-      "last_status_at": "2021-10-20T10:41:37.000Z",
+      "last_status_at": "2021-10-20",
       "emojis": [],
       "fields": [],
       "enable_rss": true,
@@ -3420,7 +3420,7 @@ func (suite *InternalToFrontendTestSuite) TestConversationToAPISelfConvo() {
       "followers_count": 2,
       "following_count": 2,
       "statuses_count": 8,
-      "last_status_at": "2024-01-10T09:24:00.000Z",
+      "last_status_at": "2024-01-10",
       "emojis": [],
       "fields": [],
       "enable_rss": true
@@ -3471,7 +3471,7 @@ func (suite *InternalToFrontendTestSuite) TestConversationToAPISelfConvo() {
       "followers_count": 2,
       "following_count": 2,
       "statuses_count": 8,
-      "last_status_at": "2024-01-10T09:24:00.000Z",
+      "last_status_at": "2024-01-10",
       "emojis": [],
       "fields": [],
       "enable_rss": true
@@ -3572,7 +3572,7 @@ func (suite *InternalToFrontendTestSuite) TestConversationToAPI() {
       "followers_count": 1,
       "following_count": 1,
       "statuses_count": 8,
-      "last_status_at": "2021-07-28T08:40:37.000Z",
+      "last_status_at": "2021-07-28",
       "emojis": [],
       "fields": [
         {
@@ -3634,7 +3634,7 @@ func (suite *InternalToFrontendTestSuite) TestConversationToAPI() {
       "followers_count": 2,
       "following_count": 2,
       "statuses_count": 8,
-      "last_status_at": "2024-01-10T09:24:00.000Z",
+      "last_status_at": "2024-01-10",
       "emojis": [],
       "fields": [],
       "enable_rss": true
diff --git a/internal/util/time.go b/internal/util/time.go
index 90e810078..0f874986a 100644
--- a/internal/util/time.go
+++ b/internal/util/time.go
@@ -21,6 +21,7 @@ import "time"
 
 // ISO8601 is a formatter for serializing times that forces ISO8601 behavior.
 const ISO8601 = "2006-01-02T15:04:05.000Z"
+const ISO8601Date = "2006-01-02"
 
 // FormatISO8601 converts the given time to UTC and then formats it
 // using the ISO8601 const, which the Mastodon API is able to understand.
@@ -28,6 +29,12 @@ func FormatISO8601(t time.Time) string {
 	return t.UTC().Format(ISO8601)
 }
 
+// Mastodon returns UTC dates (without time) for last_status_at/LastStatusAt as
+// a special case, but most of the time you want to use FormatISO8601 instead.
+func FormatISO8601Date(t time.Time) string {
+	return t.UTC().Format(ISO8601Date)
+}
+
 // ParseISO8601 parses the given time string according to the ISO8601 const.
 func ParseISO8601(in string) (time.Time, error) {
 	return time.Parse(ISO8601, in)