2018 version of paralist.sty throws error but not 2019 version

Question

I'm running texlive 2018 on ubuntu 18.04. To defeat beamer's infuriating refusal to allow users to remove spaces before and after lists, I've created my own list environment, using paralist. This runs fine on texlive 2019 but on texlive 2018 it throws this error: ! Undefined control sequence. l.12 \if@plnewenum. The obvious solution is to update to 2019, but as I've explained in this post, the recommended procedure for updating doesn't work for me. Is there a way to address the paralist error? If not, is there an alternative way to achieve the same effect, i.e., no spaces above and below the list, eg:

\documentclass{beamer}
    \usepackage{paralist}
    \newenvironment{beamerEnum}{
        \parskip=0pt
        \parindent=0pt
        \begin{compactenum}}
        {\end{compactenum}
    \parskip=12 pt plus 0 pt minus 0 pt}
    \begin{document}
    \begin{frame}{}
    Before the list
    \begin{beamerEnum}
    \item item 1
    \item item 2
    \end{beamerEnum}
    After the list
    \end{frame}
    \end{document}