Last Month Mozilla has Launched Firefox 4 but now Mozilla ready to Launched Firefox 5 with Latest Apps. Mozilla confirmed that now they will release major versions of the browser more quickly than ever.
Mozilla is now following Google Chrome approach in major versions releases. faster updates, more releases, and no waiting to bundle major features together into a bigger update that takes longer to assemble.
Mozilla has confirmed that they will release 4 major versions of Firefox in 2011. They have already released Firefox 4 one major version. Next will be released on June 21st.