More than a year and eleven - soon to be twelve - betas into the development of Firefox 4, frustration appears to be growing within developer ranks at continuing delays in the release of Mozilla's browser.

Last month, Neowin reported that Mozilla CTO and co-founder Brendan Eich had urged developers to take a hard-line on bugs slowing the release of the next major Firefox version.

Now, in a Google Group posting spotted by blog ConceivablyTech, Mozilla senior engineering director Damon Sicore has turned up the heat a little more, urging his team to ''take this hill'' and push through to ship a release candidate by February 25.

''Looking at the hardblocker bug list and not counting blocklist bugs, we have 22 bugs without patches (out of 51 open) that remain to be fixed to get to RC. This is it. It's time to do the final push to get Firefox 4 to release candidate,'' he said.