SRX Upgrade Compatibility Issue

Dear All

I am getting below error while doing upgrade of Junos from 12.1X45-D15.5 to 12.1X46-D40.2.

--------------------------------------------------------------------------------------------------------------------------------------------------------------

/config/juniper.conf:240312) syntax error at 'real'
[edit security alg]
'real disable;'
syntax error
Validation failed
Validating against /config/rescue.conf.gz
/config/rescue.conf.gz:240312) syntax error at 'real'
[edit security alg]
'real disable;'
syntax error
Validation failed
WARNING: Current configuration not compatible with /altroot/cf/packages/install-tmp/junos-12.1X46-D40.2-domestic

--------------------------------------------------------------------------------------------------------------------------------------------------------------

Kindly assist.

Regards

Harish Babu