Debugging html tag

I have the following tag in all my pages:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "">

ie console gives me a warning:

Invalid HTML5 DOCTYPE. Consider using the interoperable form "<!DOCTYPE html>".

Should I change it ?  if so what are the consequences ?
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Big MontyWeb Ninja at largeCommented:
if you are using HTML5 features, then your DocType needs to be:

<!DOCTYPE html>

if you're only using HTML4, and don't plan on upgrading, then you're fine. I would personally recommend if you do have a chance to go to HTML5, do it. for the most part, it's backwards compatible and you'll be able to take advantage of new features.

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AleksAuthor Commented:
I am using html5. That must be old code then. Thank you !
Clark KentSoftware Engineer cum BloggerCommented:

I am agree with Big Monty, This error is also coming when you are using HTML 1.0 version and add HTML 5 tags in it. To resolve this issue you have to upgrade your webpage in HTML5 version. By the using of HTML 5 and Bootstrap you can also optimize your website in device friendly layout. I hope it will be works for you. If you need any assistance, feel free to ask me.

Thanks & Regards
Clark Kent
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