diff --git a/pgscatalog_utils/validate/schemas.py b/pgscatalog_utils/validate/schemas.py
index 7997b95..cb330d8 100644
--- a/pgscatalog_utils/validate/schemas.py
+++ b/pgscatalog_utils/validate/schemas.py
@@ -50,7 +50,7 @@
 VALID_FILE_EXTENSIONS = [".txt", ".txt.gz"]
 
 # For the harmonized files
-VALID_SOURCES = ['ENSEMBL','Author-reported']
+VALID_SOURCES = ['ENSEMBL','Author-reported','liftover','Unknown']
 # VALID_CODES = ['5','4','3','1','0','-1','-4','-5']
 BUILD_LIST = ['GRCh37','GRCh38']