failed to upgrade kylin 1.2 to 1.5.0

[ianzeng]

Hi all, 

        kylin 1.5.0 has been released. I try to update kylin 1.2. to 1.5.0 
following http://kylin.apache.org/docs15/howto/howto_upgrade.html 
<http://kylin.apache.org/docs15/howto/howto_upgrade.html>. 
        After back 1.2 meta, I run 
$KYLIN_HOME/bin/kylin.sh  
org.apache.kylin.cube.upgrade.entry.CubeMetadataUpgradeEntry_v_1_5_1 
<path_of_BACKUP_FOLDER>
Error Msg return: 

Could not find or load main class 
org.apache.kylin.cube.upgrade.entry.CubeMetadataUpgradeEntry_v_1_5_1

why ?