diff --git a/requirements-swh.txt b/requirements-swh.txt
--- a/requirements-swh.txt
+++ b/requirements-swh.txt
@@ -1,4 +1,4 @@
 swh.core[db,http] >= 0.14.0
 swh.counters >= v0.8.0
-swh.model >= 4.3.0
+swh.model >= 4.4.0
 swh.objstorage >= 0.2.2
diff --git a/swh/storage/postgresql/converters.py b/swh/storage/postgresql/converters.py
--- a/swh/storage/postgresql/converters.py
+++ b/swh/storage/postgresql/converters.py
@@ -138,8 +138,8 @@
     return {
         # PostgreSQL supports isoformatted timestamps
         "timestamp": timestamp.isoformat(),
-        "offset": ts_with_tz.offset,
-        "neg_utc_offset": ts_with_tz.offset == 0
+        "offset": ts_with_tz.offset_minutes(),
+        "neg_utc_offset": ts_with_tz.offset_minutes() == 0
         and ts_with_tz.offset_bytes.startswith(b"-"),
         "offset_bytes": ts_with_tz.offset_bytes,
     }