At the moment the latest version of Softether VPN package available for arm_cortex-a9_vfpv3 is 4.28-9669-4 , Which I believe is 3 major update ( 4.32- 9731) behind the lastest Softether VPN server for linux.
New feature of the new version such as Virtual MAC for each user is missing on the current version available.
It is nearly a year since the package is released so I suggest that it should be updated.
[Sorry for the broken english]
Push, I am an active user of Softether VPN as well.