We completed the WP 4.1.1 upgrade project (originally the WP 4.1 project) on Sunday March 8th, 2015.
We kicked off WP 4.1.1 Upgrade project back in November 25th, 2014 when WP 4.1 was still in betas.
In previous upgrades, we had waited until the official release of WordPress to get started on our upgrade projects. By the time we were ready to upgrade, another release of WordPress had come out due to shorter development cycles. So our announcements for upgrades were usually not as exciting for our users.
While working on the WP 4.1 upgrade, WP 4.1.1 had been released. WP 4.1.1 had minor fixes and no database changes. We added it to our timeline without any delays or problems.
It should be mentioned that the core WP team did not keep up with their “tentative” schedule during the betas, release candidates and release. So it was hard to wait for them.