This version fixes the update checker (which had stopped working when the Mountain Utilities webhost ended support for TLS 1.0), at least for operating systems supporting TLS 1.1/1.2, i.e. OS X 10.9 (Mavericks) and later.
So on Mavericks or later, if you had disabled "Automatic check on program startup" in the "Check for update" dialog box, you can now re-enable it. And of course pressing the "Check now" button should work again too.
On OS X 10.8 (Mountain Lion) and earlier (which lack TLS 1.1/1.2 support) the update checker still doesn't work, so it's best to switch "Automatic check on program startup" off, although leaving it on will no longer prevent the application from starting up.

Main new features of this version:

• The installer automatically installs the edition of A-880 Manager matching the operating system: the 32-bit edition on 32-bit Windows, the 64-bit edition on 64-bit Windows. (Previously there was only a 32-bit edition, which was installed on 32- and 64-bit Windows alike.)
• The A-880 Manager update mechanism allows you to specify in which update types you are interested: alpha (development) versions, (‘public’) beta versions, release candidates and release versions.

See section 2 of the manual for the full list of changes.

This is the 64-bit portable edition of A-880 Manager 3.1.0 for Windows.
You don't need to install this edition: simply unzip it to a folder to which you have write-access and run A880Man.exe.
This edition only runs on 64-bit Windows.