diff --git a/mssql/functions.py b/mssql/functions.py
index 2f0fd58..1a5087e 100644
--- a/mssql/functions.py
+++ b/mssql/functions.py
@@ -281,7 +281,10 @@ def _get_check_sql(self, model, schema_editor):
         query = Query(model=model, alias_cols=False)
     else:
         query = Query(model=model)
-    where = query.build_where(self.check)
+    if VERSION >= (5, 1):
+        where = query.build_where(self.condition)
+    else:
+        where = query.build_where(self.check)
     compiler = query.get_compiler(connection=schema_editor.connection)
     sql, params = where.as_sql(compiler, schema_editor.connection)
     if schema_editor.connection.vendor == 'microsoft':