How can we install an earlier version of the package ethereum when using Ubuntu 18.04?
The currently installed version is 1.8.12 and I will like 1.8.8.
# apt-cache policy ethereum
ethereum:
  Installed: 1.8.12+build14270+bionic
  Candidate: 1.8.12+build14270+bionic
  Version table:
     1.8.12+build14270+bionic 500
        500 http://ppa.launchpad.net/ethereum/ethereum/ubuntu bionic/main amd64 Packages