LATEX~2.09 documents
LATEX2e<#548#><#548#> can process (almost) any LATEX~2.09 document, by entering
<#549#> LATEX~2.09 compatibility mode<#549#>. Nothing has changed, you run
LATEX<#550#><#550#> in the same way you always did, and you will get much the
same results.
The reason for the `almost' is that some LATEX~2.09 packages made use
of low-level unsupported features of LATEX. If you discover such a
package, you should find out if it has been updated to work with
LATEX2e. Most packages will still work with LATEX2e---the easiest way
to find out whether a package still works is to try it!
LATEX~2.09 compatibility mode is a comprehensive emulation of
LATEX~2.09, but at the cost of time. Documents can run up to 50
slower in compatibility mode than they did under LATEX~2.09.
In addition, many of the new features of LATEX2e<#551#><#551#> are not available in
LATEX~2.09 compatibility mode.