Portal New Account Approval feature

[marehem]

There is a feature in APIC v.5 Developer Portal for forcing the Admin Approval for any new accounts created in the Portal.
this feature is not available in APIC v.2018.
I know this feature "account approval" is only when Portal Delegated User Registry "PDUR" is selected and this feature is no longer available in v.2018.

So, please how can I achieve the same behavior, require admin approval for Portal new created accounts, in APIC v.2018.