diff --git a/pkg/swagger/docs.go b/pkg/swagger/docs.go
index 859df6377..ab8433634 100644
--- a/pkg/swagger/docs.go
+++ b/pkg/swagger/docs.go
@@ -4132,6 +4132,10 @@ const docTemplate = `{
                     },
                     {
                         "type": "array",
+                        "items": {
+                            "type": "string"
+                        },
+                        "collectionFormat": "csv",
                         "description": "If set to ` + "`" + `subtasks` + "`" + `, Vikunja will fetch only tasks which do not have subtasks and then in a second step, will fetch all of these subtasks. This may result in more tasks than the pagination limit being returned, but all subtasks will be present in the response. If set to ` + "`" + `buckets` + "`" + `, the buckets of each task will be present in the response. If set to ` + "`" + `reactions` + "`" + `, the reactions of each task will be present in the response. If set to ` + "`" + `comments` + "`" + `, the first 50 comments of each task will be present in the response. You can set this multiple times with different values.",
                         "name": "expand",
                         "in": "query"
@@ -4241,6 +4245,10 @@ const docTemplate = `{
                     },
                     {
                         "type": "array",
+                        "items": {
+                            "type": "string"
+                        },
+                        "collectionFormat": "csv",
                         "description": "If set to ` + "`" + `subtasks` + "`" + `, Vikunja will fetch only tasks which do not have subtasks and then in a second step, will fetch all of these subtasks. This may result in more tasks than the pagination limit being returned, but all subtasks will be present in the response. If set to ` + "`" + `buckets` + "`" + `, the buckets of each task will be present in the response. If set to ` + "`" + `reactions` + "`" + `, the reactions of each task will be present in the response. If set to ` + "`" + `comments` + "`" + `, the first 50 comments of each task will be present in the response. You can set this multiple times with different values.",
                         "name": "expand",
                         "in": "query"
diff --git a/pkg/swagger/swagger.json b/pkg/swagger/swagger.json
index 930a6871e..d0555f48a 100644
--- a/pkg/swagger/swagger.json
+++ b/pkg/swagger/swagger.json
@@ -4124,6 +4124,10 @@
                     },
                     {
                         "type": "array",
+                        "items": {
+                            "type": "string"
+                        },
+                        "collectionFormat": "csv",
                         "description": "If set to `subtasks`, Vikunja will fetch only tasks which do not have subtasks and then in a second step, will fetch all of these subtasks. This may result in more tasks than the pagination limit being returned, but all subtasks will be present in the response. If set to `buckets`, the buckets of each task will be present in the response. If set to `reactions`, the reactions of each task will be present in the response. If set to `comments`, the first 50 comments of each task will be present in the response. You can set this multiple times with different values.",
                         "name": "expand",
                         "in": "query"
@@ -4233,6 +4237,10 @@
                     },
                     {
                         "type": "array",
+                        "items": {
+                            "type": "string"
+                        },
+                        "collectionFormat": "csv",
                         "description": "If set to `subtasks`, Vikunja will fetch only tasks which do not have subtasks and then in a second step, will fetch all of these subtasks. This may result in more tasks than the pagination limit being returned, but all subtasks will be present in the response. If set to `buckets`, the buckets of each task will be present in the response. If set to `reactions`, the reactions of each task will be present in the response. If set to `comments`, the first 50 comments of each task will be present in the response. You can set this multiple times with different values.",
                         "name": "expand",
                         "in": "query"
diff --git a/pkg/swagger/swagger.yaml b/pkg/swagger/swagger.yaml
index a72c0fc52..20484241a 100644
--- a/pkg/swagger/swagger.yaml
+++ b/pkg/swagger/swagger.yaml
@@ -4506,7 +4506,8 @@ paths:
         name: id
         required: true
         type: integer
-      - description: If set to `subtasks`, Vikunja will fetch only tasks which do
+      - collectionFormat: csv
+        description: If set to `subtasks`, Vikunja will fetch only tasks which do
           not have subtasks and then in a second step, will fetch all of these subtasks.
           This may result in more tasks than the pagination limit being returned,
           but all subtasks will be present in the response. If set to `buckets`, the
@@ -4515,6 +4516,8 @@ paths:
           the first 50 comments of each task will be present in the response. You
           can set this multiple times with different values.
         in: query
+        items:
+          type: string
         name: expand
         type: array
       produces:
@@ -5440,7 +5443,8 @@ paths:
         in: query
         name: filter_include_nulls
         type: string
-      - description: If set to `subtasks`, Vikunja will fetch only tasks which do
+      - collectionFormat: csv
+        description: If set to `subtasks`, Vikunja will fetch only tasks which do
           not have subtasks and then in a second step, will fetch all of these subtasks.
           This may result in more tasks than the pagination limit being returned,
           but all subtasks will be present in the response. If set to `buckets`, the
@@ -5449,6 +5453,8 @@ paths:
           the first 50 comments of each task will be present in the response. You
           can set this multiple times with different values.
         in: query
+        items:
+          type: string
         name: expand
         type: array
       produces: