After Update Mysql 8.0.13 to 8.0.15 MySql Server Fails with error code = 1265 After Upgrading from MySql 8.0.13 (compiled from sourcecode) to MySql 8.0.15, the MySql Server can not start. 

Log: 

2019-02-12T10:09:52.275336Z 1 [ERROR] [MY-013178] [Server] Execution of server-side SQL statement 'INSERT INTO routines SELECT * FROM mysql.routines' failed with error code = 1265, error message = 'Daten abgeschnitten für Feld 'sql_mode' in Zeile 7'. 
2019-02-12T10:09:52.302630Z 0 [ERROR] [MY-010020] [Server] Data Dictionary initialization failed. 
2019-02-12T10:09:52.302856Z 0 [ERROR] [MY-010119] [Server] Aborting 


"Daten abgeschnitten für Feld" means "Data truncated for field" - its a german version ... 

table checker does not find any errors - how can I solve this problem ? 

yours sincerely 
Robert
I found the solution myself. 
On the old mysql 8.0.13 server I corrected the field SQL_MODE of one of the procedures, what happened to be too long.

SELECT * FROM INFORMATION_SCHEMA.ROUTINES;


I found some (old) stored procedures I did not need anymore, and the entries in field SQL_MODE of one of that stored procedures were too long.
After deleting that stored procedure, starting the new 8.0.15 server and "mysql_upgrade" everything is fine, the server can now start without any errors.