diff --git a/requirements-swh.txt b/requirements-swh.txt
--- a/requirements-swh.txt
+++ b/requirements-swh.txt
@@ -1,4 +1,4 @@
 swh.storage >= 0.11.3
-swh.model >= 0.4.0
+swh.model >= 4.3.0
 swh.scheduler >= 0.0.39
 swh.loader.core >= 0.18
diff --git a/swh/loader/svn/tests/test_converters.py b/swh/loader/svn/tests/test_converters.py
--- a/swh/loader/svn/tests/test_converters.py
+++ b/swh/loader/svn/tests/test_converters.py
@@ -47,9 +47,7 @@
     """
     dir_id = hash_to_bytes("d6e08e19159f77983242877c373c75222d5ae9dd")
     date = TimestampWithTimezone(
-        timestamp=Timestamp(seconds=1088108379, microseconds=0),
-        offset=0,
-        negative_utc=False,
+        timestamp=Timestamp(seconds=1088108379, microseconds=0), offset_bytes=b"+0000"
     )
     actual_rev = converters.build_swh_revision(
         repo_uuid=b"uuid",
@@ -100,16 +98,14 @@
         b"2011-05-31T06:04:39.500900Z"
     ) == TimestampWithTimezone(
         timestamp=Timestamp(seconds=1306821879, microseconds=500900),
-        offset=0,
-        negative_utc=False,
+        offset_bytes=b"+0000",
     )
 
     assert converters.svn_date_to_swh_date(
         b"2011-05-31T06:04:39.800722Z"
     ) == TimestampWithTimezone(
         timestamp=Timestamp(seconds=1306821879, microseconds=800722),
-        offset=0,
-        negative_utc=False,
+        offset_bytes=b"+0000",
     )
 
 
@@ -117,7 +113,7 @@
     """Empty date should be EPOCH (timestamp and offset at 0)."""
     # It should return 0, epoch
     default_tstz = TimestampWithTimezone(
-        timestamp=Timestamp(seconds=0, microseconds=0), offset=0, negative_utc=False,
+        timestamp=Timestamp(seconds=0, microseconds=0), offset_bytes=b"+0000"
     )
 
     assert converters.svn_date_to_swh_date("") == default_tstz