--- /dev/null
+-- @tag: letter_vendorletter
+-- @description: Briefe jetzt auch für Lieferanten
+-- @depends: release_3_4_1
+
+ALTER TABLE letter ALTER COLUMN customer_id DROP NOT NULL;
+ALTER TABLE letter ADD COLUMN vendor_id INTEGER REFERENCES vendor(id);
+
+ALTER TABLE letter_draft ALTER COLUMN customer_id DROP NOT NULL;
+ALTER TABLE letter_draft ADD COLUMN vendor_id INTEGER REFERENCES vendor(id);