It is mostly an excellent app

Unibox is quite good. I use both the Mac Mail and Unibox depending on how I want my mail sorted. I do have one serious (for me) complaint. With the latest change (I believe) the app will no longer allow me to use a custom signature. It continues to revert to “Sent with Unibox) even though I have a custom signature installed and selected. This is a major fault with the app causing me to use it far less than in the past. I have emailed the developer with no response.

Splash4358 about Unibox