diff --git a/server/mergin/sync/files.py b/server/mergin/sync/files.py
index 5e28ed70..f0ee09a1 100644
--- a/server/mergin/sync/files.py
+++ b/server/mergin/sync/files.py
@@ -254,13 +254,13 @@ def patch_field(self, data, **kwargs):
 class DeltaDiffFile:
     """Diff file path in diffs list"""
 
-    path: str
+    id: str
 
 
 class DeltaChangeDiffFileSchema(ma.Schema):
     """Schema for diff file path in diffs list"""
 
-    path = fields.String(required=True)
+    id = fields.String(required=True)
 
 
 @dataclass
@@ -287,7 +287,7 @@ def to_data_delta(self):
             version=self.version,
         )
         if self.diffs:
-            result.diff = self.diffs[0].path
+            result.diff = self.diffs[0].id
         return result
 
 
@@ -307,7 +307,7 @@ def to_merged(self) -> DeltaChangeMerged:
             version=self.version,
         )
         if self.diff:
-            result.diffs = [DeltaDiffFile(path=self.diff)]
+            result.diffs = [DeltaDiffFile(id=self.diff)]
         return result
 
 
@@ -356,6 +356,7 @@ class DeltaChangeRespSchema(ma.Schema):
     """Schema for list of delta changes wrapped in items field"""
 
     items = fields.List(fields.Nested(DeltaChangeItemSchema()))
+    to_version = fields.String(required=True)
 
     class Meta:
         unknown = EXCLUDE
diff --git a/server/mergin/sync/public_api_v2.yaml b/server/mergin/sync/public_api_v2.yaml
index b4d76944..d272b046 100644
--- a/server/mergin/sync/public_api_v2.yaml
+++ b/server/mergin/sync/public_api_v2.yaml
@@ -292,7 +292,7 @@ paths:
         - name: file
           required: true
           in: path
-          description: File path
+          description: File id of the diff file to download
           schema:
             type: string
             example: survey.gpkg-diff-1b9fe848-d2e4-4c53-958d-3dd97e5486f6
@@ -666,7 +666,7 @@ components:
           description: List of files in the project
           items:
             allOf:
-              - $ref: '#/components/schemas/File'
+              - $ref: "#/components/schemas/File"
               - type: object
                 properties:
                   mtime:
@@ -958,14 +958,17 @@ components:
           items:
             type: object
             properties:
-              path:
+              id:
                 type: string
                 example: survey.gpkg-diff-1
     ProjectDeltaResponse:
       type: object
       required:
         - items
+        - to_version
       properties:
+        to_version:
+          $ref: "#/components/schemas/VersionName"
         items:
           type: array
           items:
diff --git a/server/mergin/sync/public_api_v2_controller.py b/server/mergin/sync/public_api_v2_controller.py
index 1f9848cc..ddaf403f 100644
--- a/server/mergin/sync/public_api_v2_controller.py
+++ b/server/mergin/sync/public_api_v2_controller.py
@@ -424,20 +424,30 @@ def get_project_delta(id: str, since: str, to: Optional[str] = None):
     """Get project changes (delta) between two versions"""
 
     project: Project = require_project_by_uuid(id, ProjectPermissions.Read)
-    since = ProjectVersion.from_v_name(since)
-    to = project.latest_version if to is None else ProjectVersion.from_v_name(to)
-    if since < 0 or to < 1:
+    since_version = ProjectVersion.from_v_name(since)
+    to_provided = to is not None
+    to_version = (
+        project.latest_version if not to_provided else ProjectVersion.from_v_name(to)
+    )
+    if since_version < 0 or to_version < 0:
         abort(
             400,
-            "Invalid version number, minimum version for 'since' is 0 and minimum version for 'to' is 1",
+            "Invalid version number, minimum version for 'since' is 0 and minimum version for 'to' is 0",
         )
 
-    if to > project.latest_version:
-        abort(400, "'to' version exceeds latest project version")
-
-    if since >= to:
-        abort(400, "'since' version must be less than 'to' version")
+    if to_version > project.latest_version:
+        abort(400, "The 'to' parameter exceeds latest project version")
 
-    delta_changes = project.get_delta_changes(since, to) or []
+    if since_version > to_version:
+        abort(
+            400,
+            f"""The 'since' parameter must be less than or equal to the {"'to' parameter" if to_provided else 'latest project version'}""",
+        )
+    delta_changes = project.get_delta_changes(since_version, to_version) or []
 
-    return DeltaChangeRespSchema().dump({"items": delta_changes}), 200
+    return (
+        DeltaChangeRespSchema().dump(
+            {"to_version": f"v{to_version}", "items": delta_changes}
+        ),
+        200,
+    )
diff --git a/server/mergin/tests/test_public_api_v2.py b/server/mergin/tests/test_public_api_v2.py
index 1db387c0..25adbc89 100644
--- a/server/mergin/tests/test_public_api_v2.py
+++ b/server/mergin/tests/test_public_api_v2.py
@@ -456,7 +456,7 @@ def test_delta_merge_changes():
     assert merged[0].version == update_diff2.version
     assert merged[0].size == update_diff2.size
     assert merged[0].checksum == update_diff2.checksum
-    assert [d.path for d in merged[0].diffs] == ["diff1", "diff2"]
+    assert [d.id for d in merged[0].diffs] == ["diff1", "diff2"]
 
     # case when trying to delete already existing file in history
     # copy create with new version number
@@ -608,14 +608,14 @@ def test_project_version_delta_changes(client, diff_project: Project):
     delta = diff_project.get_delta_changes(12, latest_version.name + 6)
     assert len(delta) == 1
     assert len(delta[0].diffs) == 1
-    assert delta[0].diffs[0].path == test_gpkg_checkpoint.path
+    assert delta[0].diffs[0].id == test_gpkg_checkpoint.path
     assert delta[0].change == PushChangeType.UPDATE_DIFF
     assert delta[0].checksum == fh.checksum
     assert delta[0].size == fh.size
 
     # check if checkpoint will be there
     response = client.get(
-        f"v2/projects/{diff_project.id}/raw/diff/{delta[0].diffs[0].path}"
+        f"v2/projects/{diff_project.id}/raw/diff/{delta[0].diffs[0].id}"
     )
     assert response.status_code == 200
 
@@ -1078,6 +1078,7 @@ def test_project_delta(client, diff_project):
     assert len(changes) == 1
     assert changes[0]["change"] == PushChangeType.CREATE.value
     assert changes[0]["version"] == "v1"
+    assert response.json.get("to_version") == "v1"
 
     # remove the file and get changes from 0 -> 2 where base gpgkg is removed -> transparent
     push_change(initial_project, "removed", "base.gpkg", working_dir)
@@ -1086,6 +1087,22 @@ def test_project_delta(client, diff_project):
     changes = response.json["items"]
     assert len(changes) == 0
 
+    # get delta from 0 -> 1 where file was created
+    response = client.get(f"v2/projects/{initial_project.id}/delta?since=v0&to=v1")
+    assert response.status_code == 200
+    changes = response.json["items"]
+    assert len(changes) == 1
+    assert changes[0]["change"] == PushChangeType.CREATE.value
+    assert changes[0]["version"] == "v1"
+    assert response.json.get("to_version") == "v1"
+
+    # get delta from 1 -> 1, no changes detected
+    response = client.get(f"v2/projects/{initial_project.id}/delta?since=v1&to=v1")
+    assert response.status_code == 200
+    changes = response.json["items"]
+    assert len(changes) == 0
+    assert response.json.get("to_version") == "v1"
+
     # non valid cases
     response = client.get(f"v2/projects/{diff_project.id}/delta")
     assert response.status_code == 400
@@ -1098,9 +1115,6 @@ def test_project_delta(client, diff_project):
     # exceeding latest version
     response = client.get(f"v2/projects/{diff_project.id}/delta?since=v0&to=v2000")
     assert response.status_code == 400
-    # no changes between versions with same number
-    response = client.get(f"v2/projects/{diff_project.id}/delta?since=v1&to=v1")
-    assert response.status_code == 400
 
     # since 1 to latest version
     response = client.get(f"v2/projects/{diff_project.id}/delta?since=v1")
@@ -1117,6 +1131,8 @@ def test_project_delta(client, diff_project):
     assert changes[1]["version"] == "v9"
     assert changes[1]["path"] == "test.gpkg"
     assert changes[1]["size"] == 98304
+    # there is version without changes in v10, but exists in server
+    assert response.json.get("to_version") == "v10"
 
     # simple update
     response = client.get(f"v2/projects/{diff_project.id}/delta?since=v4&to=v8")
@@ -1127,6 +1143,7 @@ def test_project_delta(client, diff_project):
     # version is new latest version of the change
     assert changes[0]["version"] == "v7"
     assert not changes[0].get("diffs")
+    assert response.json.get("to_version") == "v8"
 
 
 def test_project_pull_diffs(client, diff_project):
@@ -1149,9 +1166,7 @@ def test_project_pull_diffs(client, diff_project):
     assert delta[0]["version"] == "v7"
     first_diff = delta[0]["diffs"][0]
     second_diff = delta[0]["diffs"][1]
-    assert first_diff["path"] == current_diffs[0].path
-    assert second_diff["path"] == current_diffs[1].path
-    response = client.get(
-        f"v2/projects/{diff_project.id}/raw/diff/{first_diff['path']}"
-    )
+    assert first_diff["id"] == current_diffs[0].path
+    assert second_diff["id"] == current_diffs[1].path
+    response = client.get(f"v2/projects/{diff_project.id}/raw/diff/{first_diff['id']}")
     assert response.status_code == 200