diff --git a/alembic/versions/0febf8c21610_dropped_column_coding_mode.py b/alembic/versions/0febf8c21610_dropped_column_coding_mode.py
new file mode 100644
index 0000000..42719e6
--- /dev/null
+++ b/alembic/versions/0febf8c21610_dropped_column_coding_mode.py
@@ -0,0 +1,37 @@
+"""dropped column coding_mode
+
+Revision ID: 0febf8c21610
+Revises: 4baf7c606f77
+Create Date: 2026-02-05 10:00:48.157541
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision: str = '0febf8c21610'
+down_revision: Union[str, Sequence[str], None] = '4baf7c606f77'
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    """Upgrade schema."""
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_column('exercise', 'coding_mode')
+    op.add_column('exercise_progress', sa.Column('failed_submissions', sa.INTEGER(), nullable=False))
+    op.add_column('exercise_progress', sa.Column('next_grading_allowed_at', sa.DateTime(timezone=True), nullable=True))
+    # ### end Alembic commands ###
+
+
+def downgrade() -> None:
+    """Downgrade schema."""
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_column('exercise_progress', 'next_grading_allowed_at')
+    op.drop_column('exercise_progress', 'failed_submissions')
+    op.add_column('exercise', sa.Column('coding_mode', sa.VARCHAR(length=3), autoincrement=False, nullable=False))
+    # ### end Alembic commands ###
diff --git a/alembic/versions/3836d6b8e3f6_failed_submissions_and_next_grading_.py b/alembic/versions/3836d6b8e3f6_failed_submissions_and_next_grading_.py
deleted file mode 100644
index 8035045..0000000
--- a/alembic/versions/3836d6b8e3f6_failed_submissions_and_next_grading_.py
+++ /dev/null
@@ -1,31 +0,0 @@
-"""failed_submissions and next_grading_allowed_at columns added to grading_job table
-
-Revision ID: 3836d6b8e3f6
-Revises: 4baf7c606f77
-Create Date: 2025-11-09 13:03:28.701620
-
-"""
-from typing import Sequence, Union
-
-import sqlalchemy as sa
-from alembic import op
-
-# revision identifiers, used by Alembic.
-revision: str = '3836d6b8e3f6'
-down_revision: Union[str, Sequence[str], None] = '4baf7c606f77'
-branch_labels: Union[str, Sequence[str], None] = None
-depends_on: Union[str, Sequence[str], None] = None
-
-
-def upgrade() -> None:
-    """Upgrade schema."""
-    # ### commands auto generated by Alembic - please adjust! ###
-    op.add_column('exercise_progress', sa.Column('skipped', sa.BOOLEAN(), nullable=False))
-    # ### end Alembic commands ###
-
-
-def downgrade() -> None:
-    """Downgrade schema."""
-    # ### commands auto generated by Alembic - please adjust! ###
-    op.drop_column('exercise_progress', 'skipped')
-    # ### end Alembic commands ###
diff --git a/app/api/schema/exercise.py b/app/api/schema/exercise.py
index e736890..66d890d 100644
--- a/app/api/schema/exercise.py
+++ b/app/api/schema/exercise.py
@@ -7,7 +7,6 @@
 class ExerciseCreate(BaseModel):
     title: str
     markdown: str
-    coding_mode: str
     skip_delay: int
     next_exercise_id: Optional[int]
 
diff --git a/app/db/model/exercise.py b/app/db/model/exercise.py
index d674eff..04f9366 100644
--- a/app/db/model/exercise.py
+++ b/app/db/model/exercise.py
@@ -9,7 +9,6 @@ class Exercise(Base):
     id = sa.Column(sa.INTEGER, default=None, primary_key=True)
     title = sa.Column(sa.TEXT, nullable=False)
     markdown = sa.Column(sa.TEXT, nullable=False)
-    coding_mode = sa.Column(sa.VARCHAR(3), nullable=False)
     next_exercise_id = sa.Column(sa.Integer, sa.ForeignKey("exercise.id"), nullable=True)
     skip_delay = sa.Column(sa.Integer, nullable=False)
 
@@ -18,7 +17,6 @@ def to_dict(self):
             "id": self.id,
             "title": self.title,
             "markdown": self.markdown,
-            "coding_mode": self.coding_mode,
             "next_exercise_id": self.next_exercise_id,
             "skip_delay": self.skip_delay,
         }