Facebook engineers speaking off the record gave the strongest signal yet that the company is addressing investor concerns about its mobile strategy and user complaints about its mobile offering.

Facebook hasn't confirmed the story, but The New York Times reported on Wednesday that Facebook engineers are working on a revision of the company's iPhone app that will make it more responsive. The Times noted that 21,000 of the App’s 38,000 reviews in Apple’s App Store give Facebook’s current iOS offering just one out of five stars, with many of the complaints focusing on speed and stability issues.

Potential Pros and Cons

Facebook will speed up the app by building the new version in the programming language Objective-C. The current app uses HTML5 in an Objective-C shell - in effect, a Web browser built within an app. Not only should the new method improve the app’s responsiveness, but it should also reduce the number of crashes that have proven to be especially frustrating to many users.

The one potential drawback: The current HTML5-in-a-shell architecture allows Facebook to make changes without requiring a full version upgrade in the app store. Most iOS users seem to be OK with regularly upgrading their favorite apps for improvements and bug fixes, but Facebook’s spotty track record of poorly publicized changes in its privacy policy could leave some users suspicious every time they’re told to update the app.

Outside of the potential need for more updates and increased speed, the new version will incorporate few changes. The new app’s user interface reportedly is identical to Facebook’s current iPhone offering.

Nick Bilton, who wrote The Times blog post and tried the new app, said it is “blazing fast.” The app is already being tested by members of Facebook’s development team and is expected to launch this summer, according to the two engineers who spoke to Bilton.