On October 1 all new links wrapped with Twitter’s t.co wrapper will use the https URL scheme. The https scheme helps Twitter securely deliver readers to the intended destination.
This scheduled change increases the length of wrapped URLs by a single character. Apps calculating available remaining characters in a Tweet should use our help/configuration API endpoint to update URL lengths; the
short_url_length property will be updated to equal the value of
short_url_length_https as all short URLs are now https.
Non-HTTPS sites may notice what appear to be lower referral numbers from Twitter as a result of the change. Web browsers drop the Referer header from a request by default when downgrading from an HTTPS t.co link to an HTTP destination in compliance with the HTTP specification for the Referer header. Twitter will use referrer policy to keep the t.co Referer for browsers supporting referrer policy. Based on our estimates you may see a 10% drop in traffic attribution from Twitter as a result of this security change, decreasing over time as users update their browsers to the latest versions supporting referrer policy.
The t.co TLS certificate is updated to extended validation with SHA-256 for supporting requestors.