I think US Sony site stops listing at v3.00...here is the latest and greatest from Europe Sony...there is no difference in firmware from different areas, just easier to locate and access on the EU and UK Sony websites.

Software: PXW-X180 : NETWORK FUNCTION V3.01 + SYSTEM V4.10 : Software/Drivers : Other : Sony Professional (http://www.pro.sony.eu/pro/lang/en/eu/support/software/SET_150904_PSG/40)