The most likely change would be for protocol to move from http to https (and for non-secure URIs to be 301 redirected/forced by HSTS) though I don't think that qualifies as a change under their rules.
Interestingly it only specifies one level of redirection. So if the redirect were from http to https, and then to some other URL, it seems like that would fail to satisfy the requirements as written.
The bet is for www.longbets.org/601, and does not include a http or https protocol. Amusingly enough www.longbets.org/601 currently redirects to longbets.org/601, though the detailed terms cover this.
The Detailed Terms section makes clear that it's for HTTP:
> …entering the characters http://www.longbets.org/601 into the address bar of a web browser or command line tool (like curl) OR using a web browser to follow a hyperlink that points to http://www.longbets.org/601 MUST …
> A 301 redirect from www.longbets.org/601 to a different URL containing that text would also fulfill those conditions.