diff --git a/backend/migrations/versions/2a4fe0f6df5b_merge_heads_after_task_custom_fields.py b/backend/migrations/versions/2a4fe0f6df5b_merge_heads_after_task_custom_fields.py
deleted file mode 100644
index 379caafe..00000000
--- a/backend/migrations/versions/2a4fe0f6df5b_merge_heads_after_task_custom_fields.py
+++ /dev/null
@@ -1,26 +0,0 @@
-"""Merge heads after task custom fields.
-
-Revision ID: 2a4fe0f6df5b
-Revises: b6f4c7d9e1a2, d3ca36cf31a1
-Create Date: 2026-02-13 21:43:07
-
-"""
-
-from __future__ import annotations
-
-
-# revision identifiers, used by Alembic.
-revision = "2a4fe0f6df5b"
-down_revision = ("b6f4c7d9e1a2", "d3ca36cf31a1")
-branch_labels = None
-depends_on = None
-
-
-def upgrade() -> None:
-    """Merge heads."""
-    pass
-
-
-def downgrade() -> None:
-    """Unmerge heads."""
-    pass
diff --git a/backend/migrations/versions/836cf8009001_merge_heads_for_activity_events_index.py b/backend/migrations/versions/836cf8009001_merge_heads_for_activity_events_index.py
deleted file mode 100644
index dc40c772..00000000
--- a/backend/migrations/versions/836cf8009001_merge_heads_for_activity_events_index.py
+++ /dev/null
@@ -1,26 +0,0 @@
-"""merge heads for activity_events index
-
-Revision ID: 836cf8009001
-Revises: b05c7b628636, fa6e83f8d9a1
-Create Date: 2026-02-13 10:57:21.395382
-
-"""
-from __future__ import annotations
-
-from alembic import op
-import sqlalchemy as sa
-
-
-# revision identifiers, used by Alembic.
-revision = '836cf8009001'
-down_revision = ('b05c7b628636', 'fa6e83f8d9a1')
-branch_labels = None
-depends_on = None
-
-
-def upgrade() -> None:
-    pass
-
-
-def downgrade() -> None:
-    pass
diff --git a/backend/migrations/versions/b05c7b628636_add_activity_events_event_type_created_.py b/backend/migrations/versions/b05c7b628636_add_activity_events_event_type_created_.py
index 4cd853e0..b91bb3f6 100644
--- a/backend/migrations/versions/b05c7b628636_add_activity_events_event_type_created_.py
+++ b/backend/migrations/versions/b05c7b628636_add_activity_events_event_type_created_.py
@@ -1,7 +1,7 @@
 """add activity_events event_type created_at index
 
 Revision ID: b05c7b628636
-Revises: bbd5bbb26d97
+Revises: b6f4c7d9e1a2
 Create Date: 2026-02-12 09:54:32.359256
 
 """
@@ -13,7 +13,7 @@ import sqlalchemy as sa
 
 # revision identifiers, used by Alembic.
 revision = 'b05c7b628636'
-down_revision = 'bbd5bbb26d97'
+down_revision = 'b6f4c7d9e1a2'
 branch_labels = None
 depends_on = None
 
diff --git a/backend/migrations/versions/bbd5bbb26d97_merge_heads.py b/backend/migrations/versions/bbd5bbb26d97_merge_heads.py
deleted file mode 100644
index 879a8335..00000000
--- a/backend/migrations/versions/bbd5bbb26d97_merge_heads.py
+++ /dev/null
@@ -1,26 +0,0 @@
-"""merge heads
-
-Revision ID: bbd5bbb26d97
-Revises: 99cd6df95f85, b4338be78eec
-Create Date: 2026-02-12 09:54:21.149702
-
-"""
-from __future__ import annotations
-
-from alembic import op
-import sqlalchemy as sa
-
-
-# revision identifiers, used by Alembic.
-revision = 'bbd5bbb26d97'
-down_revision = ('99cd6df95f85', 'b4338be78eec')
-branch_labels = None
-depends_on = None
-
-
-def upgrade() -> None:
-    pass
-
-
-def downgrade() -> None:
-    pass
diff --git a/backend/migrations/versions/d3ca36cf31a1_merge_heads_after_board_lead_rule.py b/backend/migrations/versions/d3ca36cf31a1_merge_heads_after_board_lead_rule.py
deleted file mode 100644
index 0ced45e9..00000000
--- a/backend/migrations/versions/d3ca36cf31a1_merge_heads_after_board_lead_rule.py
+++ /dev/null
@@ -1,26 +0,0 @@
-"""merge heads after board lead rule
-
-Revision ID: d3ca36cf31a1
-Revises: 1a7b2c3d4e5f, 836cf8009001
-Create Date: 2026-02-13 11:02:04.893298
-
-"""
-from __future__ import annotations
-
-from alembic import op
-import sqlalchemy as sa
-
-
-# revision identifiers, used by Alembic.
-revision = 'd3ca36cf31a1'
-down_revision = ('1a7b2c3d4e5f', '836cf8009001')
-branch_labels = None
-depends_on = None
-
-
-def upgrade() -> None:
-    pass
-
-
-def downgrade() -> None:
-    pass