clarkwinkelmann
Thank you. I am not sure if this is caused by another extension, but I've got an issue installing from the beta 13 namespace (kilowat) and for some reason it is requiring beta 14. There are also some mentions to another extension which I already have installed, so not sure why composer is complaining about it when I try to add this one.
EDIT: sorry just noticed even though I specified old namespace it was still trying to install 0.3.0, I've added the version into the composer require # composer require kilowhat/flarum-ext-mailing:^0.2.4
(not sure if the above command in your post needs it added to for other users installing). Below was what I was getting before.
# composer require kilowhat/flarum-ext-mailing
....
- kilowhat/flarum-ext-mailing 0.3.0 requires flarum/core >=0.1.0-beta.14 <0.1.0-beta.15 -> satisfiable by flarum/core[v0.1.0-beta.14, v0.1.0-beta.14.1].
- Conclusion: don't install flarum/core v0.1.0-beta.14.1