diff --git a/lib/taskana-core/src/main/resources/sql/taskana_schema_update_1.0.6_to_1.1.5._postgres.sql b/lib/taskana-core/src/main/resources/sql/taskana_schema_update_1.0.6_to_1.1.5._postgres.sql
index c6d6059b8..ff976cf66 100644
--- a/lib/taskana-core/src/main/resources/sql/taskana_schema_update_1.0.6_to_1.1.5._postgres.sql
+++ b/lib/taskana-core/src/main/resources/sql/taskana_schema_update_1.0.6_to_1.1.5._postgres.sql
@@ -4,6 +4,6 @@ SET search_path =  %schemaName%;
 
 INSERT INTO TASKANA_SCHEMA_VERSION (VERSION, CREATED) VALUES ('1.1.5', CURRENT_TIMESTAMP);
 
-ALTER TABLE TASK ADD COLUMN CALLBACK_STATE VARCHAR(30) NOT NULL DEFAULT 'NONE';
+ALTER TABLE TASK ADD COLUMN CALLBACK_STATE VARCHAR(30) NULL DEFAULT 'NONE';
 UPDATE TASK T SET CALLBACK_STATE = 'NONE';
 
diff --git a/lib/taskana-core/src/main/resources/sql/taskana_schema_update_1.0.6_to_1.1.5.sql b/lib/taskana-core/src/main/resources/sql/taskana_schema_update_1.0.6_to_1.1.5.sql
index 657908ffc..11786a323 100644
--- a/lib/taskana-core/src/main/resources/sql/taskana_schema_update_1.0.6_to_1.1.5.sql
+++ b/lib/taskana-core/src/main/resources/sql/taskana_schema_update_1.0.6_to_1.1.5.sql
@@ -4,6 +4,6 @@ SET SCHEMA %schemaName%;
 
 INSERT INTO TASKANA_SCHEMA_VERSION (VERSION, CREATED) VALUES ('1.1.5', CURRENT_TIMESTAMP);
 
-ALTER TABLE TASK ADD COLUMN CALLBACK_STATE VARCHAR(30) NOT NULL DEFAULT 'NONE';
+ALTER TABLE TASK ADD COLUMN CALLBACK_STATE VARCHAR(30) NULL DEFAULT 'NONE';
 UPDATE TASK T SET CALLBACK_STATE = 'NONE';