The Twitter through its Developers page has revealed that by February 20th, 2013 next year, there are going to be two fewer characters to send a message on Twitter at the time when you share a link, means now the t.co wrapper will have 20 to 22 reserved characters which takes up two more spaces that one could previously use for letters. The new structure will be like this: HTTP links will have 20 to 22 and HTTPS (secure) links will have 21 to 23 characters reserved.
Here is what Twitter has to say about it:
We’d like to share some upcoming changes to our t.co link wrapper with the ecosystem. We’re going to be extending the maximum length of t.co wrapped links from 20 to 22 characters for non-https URLs, and 21 to 23 characters for https URLs.
To give everyone enough time to update their applications, this change won’t go into effect for two months – so please consider this a heads up. On February 6th, 2013, the GET help/configuration method will start to return the updated values for the length of characters returned in the following key-value pairs:
Two weeks later on February 20th, 2013, we will begin generating and returning t.co URLs with this new maximum length. Ensure that your application is prepared to handle this change by that date.