diff --git a/docs/changeset.rst b/docs/changeset.rst
index ab5993b..80e350a 100644
--- a/docs/changeset.rst
+++ b/docs/changeset.rst
@@ -28,7 +28,7 @@ Summary of supported actions:
 
 * :meth:`Create a column <ChangesetColumn.create>`
 * :meth:`Drop a column <ChangesetColumn.drop>`
-* :meth:`Alter a column <ChangesetColumn.alter>` (name, nullabe, type, server_default)
+* :meth:`Alter a column <ChangesetColumn.alter>` (follow a link for list of supported changes)
 * :meth:`Rename a table <ChangesetTable.rename>`
 * :meth:`Rename an index <ChangesetIndex.rename>`
 * :meth:`Create primary key constraint <migrate.changeset.constraint.PrimaryKeyConstraint>`
diff --git a/migrate/changeset/schema.py b/migrate/changeset/schema.py
index f64e595..32a2a8f 100644
--- a/migrate/changeset/schema.py
+++ b/migrate/changeset/schema.py
@@ -178,7 +178,7 @@ class ColumnDelta(DictMixin, sqlalchemy.schema.SchemaItem):
 
         * :class:`ColumnDelta`.current_name is current name of column in db
 
-        
+
     """
 
     # Column attributes that can be altered
@@ -474,6 +474,9 @@ class ChangesetColumn(object):
 
             col.alter(name='foobar', type=Integer(), server_default=text("a"))
 
+        Supported parameters: name, type, primary_key, nullable,
+        server_onupdate, server_default, autoincrement
+
         """
         if 'table' not in k:
             k['table'] = self.table
diff --git a/migrate/tests/versioning/test_version.py b/migrate/tests/versioning/test_version.py
index 0be192f..9ef15ef 100644
--- a/migrate/tests/versioning/test_version.py
+++ b/migrate/tests/versioning/test_version.py
@@ -83,6 +83,7 @@ class TestVersion(fixture.Pathed):
         self.assertEquals(str_to_filename('Abc "D" Ef'), 'Abc_D_Ef')
         self.assertEquals(str_to_filename("Abc's Stuff"), 'Abc_s_Stuff')
         self.assertEquals(str_to_filename("a      b"), 'a_b')
+        self.assertEquals(str_to_filename("a.b to c"), 'a_b_to_c')
 
     def test_collection(self):
         """Let's see how we handle versions collection"""
diff --git a/migrate/versioning/version.py b/migrate/versioning/version.py
index 11f7aa0..04445a3 100644
--- a/migrate/versioning/version.py
+++ b/migrate/versioning/version.py
@@ -208,7 +208,7 @@ def str_to_filename(s):
     and double underscores to underscores
     """
 
-    s = s.replace(' ', '_').replace('"', '_').replace("'", '_')
+    s = s.replace(' ', '_').replace('"', '_').replace("'", '_').replace(".", "_")
     while '__' in s:
         s = s.replace('__', '_')
     return s