Is using the struts.mapper.action.prefix.enabled safe?

[Gavin Donald]

Hello,

While upgrading Struts from 2.3.15 I came across the information that 
DMI is disabled. at http://tinyurl.com/zaveghr it states that I can use 
/struts.mapper.action.prefix.enabled/ and that works for my use case. I 
am however a little unclear if it is safe to use or if it simply enables 
parts of DMI that are unsafe.

If it is unsafe is the correct way to have multiple submit buttons in a 
form to use a custom ActionMapper?

Thanks.

Gavin.