Beginning with version 2.2, the Alpha LaTeX macros support LaTeX2e, a superset of LaTeX 2.09. LaTeX2e will typeset a 2.09 document automatically, using what is called ``compatibility mode''. Most of the LaTeX 2.09 commands and environments have been preserved in 2e, making the transition from 2.09 to 2e relatively painless (from the user's point of view, at least).
For those who have not yet upgraded to LaTeX2e, the old LaTeX 2.09 macros are still available. Just choose LaTeX 2.09 on the Install submenu of the Config menu and follow the prompts to install the old version. Note, however, that all present and future enhancements to the Alpha LaTeX macros will be directed towards LaTeX2e users, and so you are encouraged to upgrade your TeX implementation as soon as possible.