\begin{tabular}[hbt]{| l || c | c | c |}
	\hline
	Requirement & Importance & Pending work & Focus \\
	\hline \hline
	\RF1: In/out channels    & ++ & - & + \\
	\hline
	\RF2: Mail queue         & ++ & - & + \\
	\hline
	\RF3: Header sanitizing  & 0 & - & - \\
	\hline
	\RF4: Aliasing           & 0 & - & - \\
	\hline
	\RF5: Route selection    & + & - & 0 \\
	\hline
	\RF6: Authentication     & ++ & + & +++ \\
	\hline
	\RF7: Encryption         & ++ & + & +++ \\
	\hline
	\RF8: Spam prevention    & + & ++ & +++ \\
	\hline
	\RF9: Malware handling   & - & + & 0 \\
	\hline
	\RF10: Archiving         & - & + & 0 \\
	\hline
	\hline
	\RG1: Security           & ++ & + & +++ \\
	\hline
	\RG2: Reliability        & ++ & + & +++ \\
	\hline
	\RG3: Robustness         & + & + & ++ \\
	\hline
	\RG4: Extendability      & + & ++ & +++ \\
	\hline
	\RG5: Maintainability    & + & 0 & + \\
	\hline
	\RG6: Testability        & 0 & 0 & 0 \\
	\hline
	\RG7: Performance        & -{}- & - & -{}-{}- \\
	\hline
	\RG8: Availability       & - & - & -{}- \\
	\hline
	\RG9: Portability        & - & -{}- & -{}-{}- \\
	\hline
	\RG10: Usability         & + & -{}- & - \\
	\hline
\end{tabular}