We just recently upgraded from SM15 to SM16 and were excited to learn about the "send as alias feature", unfortunately, it only works with the primary domain and not domain aliases so we still have to setup tons of SMTP accounts. For example, we have 4 brands (branda.com, brandb.com, brandc.com, and brandd.com) but b, c, and d are just aliases of a. We also have email aliases like "accounting@" that goes to our 4 accountants. In SM15 we had to setup "accounting@" as a real user instead of an alias and then setup 4 SMTP accounts for each user. In SM16, we can make it an alias, but in the web interface the users can only send out as accounting@branda.com and now as the other 3. :'(