screenshot by Stephen Shankland/CNET

Mozilla announced on Wednesday it's finished Firefox OS 1.1, filling in a large number of missing features, improving performance, and securing some new commitments from carriers that are helping back the browser-based operating system for mobile phones.

Firefox 1.0 debuted earlier this year for the first generation of mobile phones, generally low-end models targeted at feature-phone owners who wanted to take the smartphone plunge but who didn't want to spend the money required for higher-end Android or iOS devices. As with many first-version operating systems, though, there were a lot of missing pieces.

Now, along with performance improvements including smoother scrolling and faster app loading, a host of those missing pieces have been added, according to a blog post by Chris Lee, director of the Firefox OS product. Among the new features, which are due to ship to Firefox OS users "soon," are the following:

Promotion of the adaptive app search feature to the home screen. The feature lets people type to search for apps stored on their phone to get a list of Web sites and apps and bookmark ones they like for later use. (People also can find apps through the Firefox Marketplace.)

The ability to import contacts from Google's Gmail and Microsoft's Hotmail, not just from Facebook.

Support for picture messaging with MMS (Multimedia Messaging Service).

A programming interface to let developers send push notifications.

Autocorrect for keyboard typing.

Music search, which lets people swipe down from the top of the music app to find music based on artist, song, or album.

The ability to save photos, videos, and audio from the browser.

The ability to save draft e-mails, to download audio and video e-mail attachments, and to attach gallery images to e-mails.

The ability to long-press on an entry from a call log to add that information to a new or existing entry in the contact list.

The ability to create a new calendar entry by tapping on the desired time slot on the calendar.

Firefox OS is key to Mozilla's attempt to stay relevant in an era in which people use mobile phones and tablets as well as personal computers. The nonprofit organization's mission is to keep the Web open, and an important part of that is influencing Web standards. Having a lot of users means that Mozilla's support for new standards -- or its decisions not to support them -- can have a lot of influence on the future of the Web. If Firefox isn't used, though, that influence dwindles.

"Existing Firefox OS users will be upgraded to the latest version soon," Mozilla said in a separate blog post. Deutsche Telekom predicted it would be available as an over-the-air update in upcoming days.

Because there are multiple phone models on the market, Firefox OS updates will be distributed more like Android updates than iOS updates, said Telenor spokesman Atle Lessum. "We will be securing the customer experience when an upgrade is available," he said. "We will do this in close cooperation with the device manufacturer in the different markets."

Carrier allies speak out

Carriers are central to Mozilla's Firefox OS plans, and on Tuesday, the first three partners expanded on their plans for the phones.

Firefox OS device sales in Spain, Colombia, and Venezuela "have surpassed our expectations," said Yotam Ben-Ami, director of open web devices at Telefonica, Mozilla's initial Firefox OS partner. "We now look forward to bringing the benefits of Firefox OS to our customers in Brazil and three other Latin America markets during Q4 2013 as well as making it available through many more Telefonica operating businesses during 2014."

Another carrier, Telenor, said it will bring Firefox OS phones to Hungary, Serbia, and Montenegro this year. Sales in the company's Asian markets will take place after that, the company said.

Thomas Kiessling, chief product and innovation officer at Deutsche Telekom, called his company's launch of Firefox OS phones in Poland "very successful" and said it will begin selling the phones to customers of its Congstar brand in Germany. It will introduce the phones in Greece and Hungary "soon," he said.

Hard transition

The mobile-computing transition has been hard for Mozilla. Firefox has a vanishingly small presence on Android phones and in effect can't run on iOS, Windows Phone, or Windows RT, so Firefox OS is central the organization's push for relevance. Gaining a foothold against Android, which is spreading rapidly to low-cost phones in new markets, intensifies Mozilla's challenge.

Firefox OS is a browser-based operating system, meaning that is uses the same browser rendering engine at the heart of Firefox running on PCs not just to display Web pages but also to run Web apps. Mozilla has pushed a suite of Web standards that give Web apps many of the abilities that native apps get on rival OSes like iOS and Android.

Mozilla has attracted a large number of partners, though -- notably mobile network operators that would like alternatives that don't cede as much control to the Google and Apple juggernauts.

"We know that a smartphone ecosystem needs time to evolve. Look at Android," said Deutsche Telekom spokeswoman Marion Kessing. "The goal with a first phone is always to prepare the ground... We want to clear the way for Firefox OS."

Carriers selling Firefox OS phones have settled on two models so far, the ZTE Open and the Alcatel One Touch Fire. A smaller smartphone maker, Geeksphone, has committed to shipping Firefox OS 1.1 on its Peak+ phone.

Updated at 4:40 a.m. PT and 6:42 a.m. PT with details and comment from Firefox OS carrier partners.