Add missing documentation fix

docs/user-guide/installation/source.tex

@@ -233,7 +233,7 @@ parallel execution\\
 GSMPI           &        &                  &        & \cmark & For
 parallel execution\\
 HDF5            &        & \cmark & \cmark & \cmark & For
-large-scale parallel I/O\\
+large-scale parallel I/O (requires CMake >3.1)\\
 PETSc           &        & \texttt{petsc}   & \cmark & \cmark &
 Alternative linear solvers\\
 Scotch          &        & \texttt{scotch}  & \cmark & \cmark &
@@ -573,7 +573,8 @@ can be selected using the following options:
     parallel file format, which can be very efficient for large numbers of
     processes. HDF5 output can be enabled by using a command-line option or
     in the \inlsh{SOLVERINFO} section of the XML file. This option requires 
-    that \nekpp be built with MPI support with \inlsh{NEKTAR\_USE\_MPI} enabled.
+    that \nekpp be built with MPI support with \inlsh{NEKTAR\_USE\_MPI} enabled
+    and that HDF5 is compiled with MPI support.
 
     \item \inlsh{NEKTAR\_USE\_MKL}