Updating SAP NW Java 7.01 to NW 7.40 SR1 on High Availaibility

Hello,

I have to upgrade SAP Netweaver Java system 7.01 to 7.40 SR1 using SUM.

Environnement is in Windows Cluster HA.

Regarding SUM Guide, I need to uninstall ERS on both nodes before downtime and them reinstall ERS after downtime.

Is it mandatory to do that?

When ugrading ABAP system (HA too) from ECC6 EhP4 (NW 7.01) to ECC6 EhP7, I did'nt have to do this and I didn't have any problem. System was ugraded well.

Thanks for your help !

Regards