Query: Will uninstalling smail result in breaking of any other packages?

[rajibando]

This query is in connection with my other post, Query: How to Set Up a local smtp email server from own system?

The query is pertinent for my Knoppix 7.2.0.
But why didn't I upgrade to the latest version? Because the version works perfectly well for my laptop and is sufficient for my daily computing needs.

[rajibando]

smail
Reverse Depends:

 |uucp
  rmail
  postfix
  exim4-config

Among the four, only rmail is installed.

rmail: /usr/bin/rmail /usr/sbin/rmail /usr/bin/X11/rmail /usr/share/man/man8/rmail.8.gz

rmail
Reverse Depends:

  uucp
  sendmail

uucp
Reverse Depends:

  tua
  uucp-lmtp
  uucpsend
  cu

None installed. So shall I proceed and install exim4?
I checked Debian archive for ancient obsolete releases. Presently, doesn't appear to be working. Any information about the smail package's origins would have helped.