Html Helper in Meta tag

At the moment CI is generating HTML 4.1 valid output.
How ever you are right that HTML5 is already on stage.
Perhaps those helpers needs to get an improvement to start supporting different HTML standards.
Only this way we will have support over both HTML5 and HTML4 and all the future versions.

I have moved all my new development to HTML5.

I understand the consequences to this, but it seems that the more people who move forward and keep going forward, the better adoption there will be of the more recent standards.

Besides, most of the people still using 10 year old computers, are not the types to be buying or using new things.