jeffkee
I completely understand the use case, but I believe this feature might be less practical in real-world scenarios than it initially seems.
For example, when performing a migration between cPanel servers (and I believe also between Plesk servers and from cPanel to Plesk), the migration system automatically updates all IP addresses from the old server to those of the new one.
This makes sense because — in most cases — the new server belongs to a different datacentre or provider, which means it’s not possible to reuse the IP ranges from the previous server.
Imagine, for instance, migrating from OVH to Hetzner: it’s simply not possible to assign an OVH IP address to a Hetzner machine, since they belong to completely separate autonomous systems and networks.
Therefore, while supporting multiple IP addresses on a single server could be useful for internal transitions (within the same provider), it wouldn’t really solve the problem in cross-provider migrations, because IPs aren’t portable between datacentres or network operators.
In practice, a controlled DNS migration (with reduced TTLs and pre-validation) is usually a safer and more consistent solution than trying to keep both IPs active at the same time.
That said, I agree that Enhance could eventually introduce a feature such as a “temporary” or “alias” IP for advanced scenarios — but its usefulness would likely remain limited to situations within the same network infrastructure.