Wine won't install, Does not have valid release file

I'm trying to install wine on Ubuntu Mate 18.04. Whenever I add the repository I get the error message

Blockquote E: The repository 'http://ppa.launchpad.net/ubuntu-wine/ppa/ubuntu bionic Release' does not have a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details.

It's given the same error message for a few other programs I've tried to install too. Is it because 18.04 is so new it doesn't officially support it yet?

18.04 has been out for less than a week. As such, many developers haven't caught up to the new release yet. To that end, WineHQ has a bug for this already requesting 18.04 packaging in their repository.

There is Wine 3.0 in the Ubuntu repositories, you can use that in the interim by executing sudo apt install wine. Once the upstream WineHQ repositories catch up you can use them.

Once that time is available, you can follow the instructions for installing from their repos. From their instructions page are the instructions to follow at that time:

If you have previously installed a Wine package from another repository, please remove it and any packages that depend on it (e.g., wine-mono, wine-gecko, winetricks) before attempting to install the WineHQ packages, as they may cause dependency conflicts.

If your system is 64 bit, enable 32 bit architecture (if you haven't already):

sudo dpkg --add-architecture i386 

Add the repository:

wget -nc https://dl.winehq.org/wine-builds/Release.key
sudo apt-key add Release.key
sudo apt-add-repository https://dl.winehq.org/wine-builds/ubuntu/

Update packages:

sudo apt-get update

Then install one of the following packages:

Stable Branch:

sudo apt-get install --install-recommends winehq-stable

Development Branch:

sudo apt-get install --install-recommends winehq-devel

Staging Branch:

sudo apt-get install --install-recommends winehq-staging

If apt-get complains about missing dependencies, install them, then repeat the last two steps (update and install).

Staging isn't really used anymore, so use either Stable or Devel.

There will be differences though:

• Files are installed to /opt/wine-devel.

• Menu items are not created for Wine's builtin programs (winecfg, etc.), and if you are upgrading from a distro package that had added them, they will be removed. You can recreate them yourself using your menu editor.

• Binfmt_misc registration is not added. Consult your distro's documentation for update-binfmts if you wish to do this manually.

• WineHQ does not at present package wine-gecko or wine-mono. When creating a new wine prefix, you will be asked if you want to download those components. For best compatibility, it is recommended to click Yes here. If the download doesn't work for you, please follow the instructions on the Gecko and Mono wiki pages to install them manually.