This milestone is completely in the light of extended Views integration. In 6.x-2.0-alpha2, you already had "basic" Views integration, meaning you could create a view of addresses using fields. The 6.x-2.0-beta1 version brings much more, especially access related features. This are the new features:
Create a View using the address row style, allowing you to create an address listing themed just like in the address book;
When using fields: view, edit and delete links;
Filter the View by address access;
In arguments/contextual filters: validators for address access;
Address access checks for Views displays;
A View to replace the address book page (this View is disabled by default).
Changes since 6.x-2.0-alpha2
API changes
Issue #1894858 by MegaChriz: made API change in UcAddressesPermissions to be able to check access for other users.
Issue #1831424 by MegaChriz: backported API additions from the 7.x-1.x version.
Issue #1910626 by MegaChriz: API change: specified field data types.