diff --git a/swh/loader/package/deposit/tests/data/https_deposit.softwareheritage.org/hello_2.10.json b/swh/loader/package/deposit/tests/data/https_deposit.softwareheritage.org/hello_2.10.json
--- a/swh/loader/package/deposit/tests/data/https_deposit.softwareheritage.org/hello_2.10.json
+++ b/swh/loader/package/deposit/tests/data/https_deposit.softwareheritage.org/hello_2.10.json
@@ -41,8 +41,7 @@
         "seconds": 1507389428,
         "microseconds": 0
       },
-      "offset": 0,
-      "negative_utc": false
+      "offset": 0
     },
     "committer": {
       "name": "Software Heritage",
@@ -54,8 +53,7 @@
         "seconds": 1507389428,
         "microseconds": 0
       },
-      "offset": 0,
-      "negative_utc": false
+      "offset": 0
     },
     "revision_parents": [],
     "release_notes": null
diff --git a/swh/loader/package/deposit/tests/data/https_deposit.softwareheritage.org/hello_2.11.json b/swh/loader/package/deposit/tests/data/https_deposit.softwareheritage.org/hello_2.11.json
--- a/swh/loader/package/deposit/tests/data/https_deposit.softwareheritage.org/hello_2.11.json
+++ b/swh/loader/package/deposit/tests/data/https_deposit.softwareheritage.org/hello_2.11.json
@@ -44,8 +44,7 @@
         "seconds": 1507389428,
         "microseconds": 0
       },
-      "offset": 0,
-      "negative_utc": false
+      "offset": 0
     },
     "committer": {
       "name": "Software Heritage",
@@ -57,8 +56,7 @@
         "seconds": 1507474800,
         "microseconds": 0
       },
-      "offset": 0,
-      "negative_utc": false
+      "offset": 0
     },
     "revision_parents": [],
     "release_notes": null
diff --git a/swh/loader/package/deposit/tests/data/https_deposit.softwareheritage.org/hello_2.12.json b/swh/loader/package/deposit/tests/data/https_deposit.softwareheritage.org/hello_2.12.json
--- a/swh/loader/package/deposit/tests/data/https_deposit.softwareheritage.org/hello_2.12.json
+++ b/swh/loader/package/deposit/tests/data/https_deposit.softwareheritage.org/hello_2.12.json
@@ -44,8 +44,7 @@
         "seconds": 1507389428,
         "microseconds": 0
       },
-      "offset": 0,
-      "negative_utc": false
+      "offset": 0
     },
     "committer": {
       "name": "Software Heritage",
@@ -57,8 +56,7 @@
         "seconds": 1507474800,
         "microseconds": 0
       },
-      "offset": 0,
-      "negative_utc": false
+      "offset": 0
     },
     "revision_parents": [],
     "release_notes": null
diff --git a/swh/loader/package/deposit/tests/data/https_deposit.softwareheritage.org/hello_2.13.json b/swh/loader/package/deposit/tests/data/https_deposit.softwareheritage.org/hello_2.13.json
--- a/swh/loader/package/deposit/tests/data/https_deposit.softwareheritage.org/hello_2.13.json
+++ b/swh/loader/package/deposit/tests/data/https_deposit.softwareheritage.org/hello_2.13.json
@@ -44,8 +44,7 @@
         "seconds": 1507389428,
         "microseconds": 0
       },
-      "offset": 0,
-      "negative_utc": false
+      "offset": 0
     },
     "committer": {
       "name": "Software Heritage",
@@ -57,8 +56,7 @@
         "seconds": 1507474800,
         "microseconds": 0
       },
-      "offset": 0,
-      "negative_utc": false
+      "offset": 0
     },
     "revision_parents": [],
     "release_notes": "This release adds this and that."
diff --git a/swh/loader/package/deposit/tests/test_deposit.py b/swh/loader/package/deposit/tests/test_deposit.py
--- a/swh/loader/package/deposit/tests/test_deposit.py
+++ b/swh/loader/package/deposit/tests/test_deposit.py
@@ -330,13 +330,13 @@
     # Retrieve the release
     release = loader.storage.release_get([hash_to_bytes(release_id)])[0]
     assert release
-    release_date_dict = release.date.to_dict()
+    # swh-deposit uses the numeric 'offset' instead of 'offset_bytes' because its dates
+    # are always well-formed, and it can only send JSON-serializable data.
+    release_date_dict = {
+        "timestamp": release.date.timestamp.to_dict(),
+        "offset": release.date.offset,
+    }
 
-    # Workaround while we migrate from storing offsets as (int, bool) to bytes.
-    # When the migration is done, remove this pop().
-    # offset_bytes will also need to be converted to a string (which is fine because
-    # it is always a well-formed offset)
-    release_date_dict.pop("offset_bytes", None)
     assert release_date_dict == raw_meta["deposit"]["author_date"]
 
     assert not release.metadata