Hi,

Can we configure the dead subscriptions for UM queue or topic ?

In case of broker we can. If condition doesn’t match and dead letter queue is configured then broker send the document to dead letter queue.

But how we can do this it for UM queue and topic

You have to configure “Dead Event Store” to handle this:

Dead Event Store
When events are removed automatically, either by the capacity policy of the channel or
the age (TTL) policy of the individual events, and they have not been consumed, it may
be a requirement for those events to be processed separately. If so, channels or queues
can be created with a dead event store so any events that are purged automatically
before being consumed will be moved into the dead event store. Dead event stores
themselves can be a channel or a queue and can be created with any attributes you wish.