I agree with Ivantcholakov, but I understand where you are coming from. Perhaps the time and effort does not feel warranted because it feels like a big job. Perhaps the security fixes that have been done since your version do not cause you any concern. Perhaps your server/host will continue to offer php 5 even though active support has ended for all but 5.6 which will end in 6 months time. Perhaps you do not intend to upgrade your application with any new features, or if you do are happy to work around the hundreds of bugs and issues with the old CI version 2. Some companies choose to run old vehicles and put up with the breakdowns, higher safety risks and unreliability. Some companies find their old rolling stock works fine. Some companies continue to use windows XP. Sometimes it is purely a monetary issue, where the cost appears to be too exorbitant for something that appears to be working fine, and the risks taken by running an insecure and hackable system on old, unsupported technologies are considered non mission critical.
If all your technological expertise has found no issues with CI2, and all your research into the topic can find no security problems, you can confidently stride into the future knowing that your systems are fine, and all this security lark is a bit of hype by security people selling services.
Who knows, perhaps you are right and your system will avoid a catastrophic hack, an un-fixable error, or a failure on a hosting upgrade, and will sail happily into the future for years to come. You can look back on saving yourself a week or twos work upgrading, or perhaps congratulate yourself on saving a small IT expenditure. Well done you.
Or perhaps one day you will come into work to find suddenly nothing works. Or all your data has been stolen, or destroyed, and find yourself explaining to your colleagues why, with your deep understanding of technology, and all your research, you were unable to forsee any potential risks.
Good luck,
Paul.
PS Whats your domain name? Perhaps we can have a play on your 2.0 systems? Some of the security problems were made public and we can test them for you. It might be fun taking a look at your data. Promise not to do anything naughty - you know how trustworthy the open internet can be :-)
