diff --git a/database/upgrades/00-latest-revision.sql b/database/upgrades/00-latest-revision.sql
index f0a1b6e..5920ffa 100644
--- a/database/upgrades/00-latest-revision.sql
+++ b/database/upgrades/00-latest-revision.sql
@@ -1,4 +1,4 @@
--- v0 -> v48: Latest revision
+-- v0 -> v49: Latest revision
 
 CREATE TABLE "user" (
     mxid     TEXT PRIMARY KEY,
@@ -127,7 +127,7 @@ CREATE TABLE backfill_state (
     portal_receiver   TEXT,
     processing_batch  BOOLEAN,
     backfill_complete BOOLEAN,
-    first_expected_ts TIMESTAMP,
+    first_expected_ts BIGINT,
     PRIMARY KEY (user_mxid, portal_jid, portal_receiver),
     FOREIGN KEY (user_mxid) REFERENCES "user" (mxid) ON DELETE CASCADE ON UPDATE CASCADE,
     FOREIGN KEY (portal_jid, portal_receiver) REFERENCES portal (jid, receiver) ON DELETE CASCADE
diff --git a/database/upgrades/47-room-backfill-state.sql b/database/upgrades/47-room-backfill-state.sql
index 40e052a..18d3efe 100644
--- a/database/upgrades/47-room-backfill-state.sql
+++ b/database/upgrades/47-room-backfill-state.sql
@@ -6,7 +6,7 @@ CREATE TABLE backfill_state (
     portal_receiver   TEXT,
     processing_batch  BOOLEAN,
     backfill_complete BOOLEAN,
-    first_expected_ts TIMESTAMP,
+    first_expected_ts INTEGER,
     PRIMARY KEY (user_mxid, portal_jid, portal_receiver),
     FOREIGN KEY (user_mxid) REFERENCES "user" (mxid) ON DELETE CASCADE ON UPDATE CASCADE,
     FOREIGN KEY (portal_jid, portal_receiver) REFERENCES portal (jid, receiver) ON DELETE CASCADE
diff --git a/database/upgrades/49-backfill-state-timestamp-bigint.sql b/database/upgrades/49-backfill-state-timestamp-bigint.sql
index b2128ee..fb32a53 100644
--- a/database/upgrades/49-backfill-state-timestamp-bigint.sql
+++ b/database/upgrades/49-backfill-state-timestamp-bigint.sql
@@ -1,7 +1,13 @@
--- v49: Convert first_expected_ts to BIGINT so that we can use zero-values.
-
--- only: sqlite
-UPDATE backfill_state SET first_expected_ts=unixepoch(first_expected_ts);
-
+-- v49: Convert first_expected_ts to BIGINT
 -- only: postgres
-ALTER TABLE backfill_state ALTER COLUMN first_expected_ts TYPE BIGINT USING extract(epoch from first_expected_ts);
+
+DO
+$do$
+BEGIN
+    IF (SELECT data_type FROM information_schema.columns WHERE table_name='backfill_state' AND column_name='first_expected_ts') = 'integer' THEN
+        ALTER TABLE backfill_state ALTER COLUMN first_expected_ts TYPE BIGINT;
+    ELSE
+        ALTER TABLE backfill_state ALTER COLUMN first_expected_ts TYPE BIGINT USING EXTRACT(EPOCH FROM first_expected_ts);
+    END IF;
+END
+$do$