I have an asp.net web forms application that has been live for a number of years and as such has quite a lot of indexed content on google.
Ideally, I'd prefer that all Url's for the website are in lowercase but I understand that having 2 versions of the same content indexed in search engines (MixedCase.aspx and mixedcase.aspx) will be bad for seo.
I was wondering:
a) Should I just leave everything in its current Mixed Case form and never change it?
OR
b) I can change the code so everything is in lowercase from here on in, BUT, is there a way of doing this so as the search engines are aware of this change and don't penalise me?
Having two versions of the same URL will cause duplicate content issues, although the search engines are generally smart enough to know that the two pages are the same.
There are two good solutions. The first is to use the canonical meta tag to specify your preferred version of the URL. With this solution, both MixedCase.aspx and mixedcase.aspx would show the same page, but the search engines know for definite which is the "correct" URL to show. Make sure you update all your links to the lowercase version.
The second solution is to use 301 Redirects. Usually this is preferred because users will always wind up at the correct page. If they decide to link to it, they're using the correct version. As Rocky says, the redirects will need to stay in place permanently if you already have links from other sites. However, technical (or time) limitations may mean you need to use the canonical method.