The BCH Unlimited Ubuntu PPA repository has been updated to serve version 1.9.0 is available at:

https://launchpad.net/~bitcoin-unlimited/ archive/ubuntu/bucash

This release is compatible the Bitcoin Cash protocol. To update already installed packages:

sudo apt update 
sudo apt upgrade

To install

sudo add-apt-repository ppa:bitcoin-unlimited/bucash
sudo apt-get update
sudo apt install bitcoind bitcoin-qt

starting from this update the repository is serving also ElectrsCash(**) v2.0.0, for now just for the amd64 architecture. To install it just execute this command:

sudo apt install electrscash

See the official announcement and the release notes for more details:

https://old.reddit.com/r/btc/comments/ih2eyt/bch_unlimited_190_has_just_been_released/

https://github.com/BitcoinUnlimited/BitcoinUnlimited/blob/release/doc/release-notes/release-notes-1.9.0.md

Known issues:

On Ubuntu 18.04 (bionic) you'll probably get an error while trying to install bitcoind. The error message is the following:

The following packages have unmet dependencies.
bitcoind : Depends: libgcc-s1 (>= 3.4) but it is not installable
E: Unable to correct problems, you have held broken packages.

Package libgcc-s1 is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source

To solve the problem please do:

sudo add-apt-repository ppa:ubuntu-toolchain-r/test
sudo apt update 
sudo apt dist-upgrade
sudo apt install bitcoind 

(**) ElectrsCash is an efficient re-implementation of Electrum Server written in Rust.