At last I had the dare to upgrade my Nokia E70’s firmware with Nokia Software Updater. Nothing special, happy ending. The new version is numbered 2.0618.07.10.
New firmware seems to be more stable and especially the internet browser doesn’t crash and complain all the time about the unsufficient memory. I also installed the new Opera mini 3.0 and the F-secure’s Mobile Security which contains anti-virus and firewall. And I also got some new ring tones 😉