How to handle existing indexed Mixed Case url's?
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?
How to handle existing indexed Mixed Case url's?
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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?