The grace period (i.e the period from when a domain name is suspended until it is deleted) for .is domains has been 60 days since .is domain names were available. This period will soon be shortened to 30 days, counting from the renewal date.
The reason for this is simply to get deleted domains one month sooner back on the market, and to align the .is domain rules to international conventions. After this change ISNIC will also inform the registrant precisely when the domain will be deleted, regardless of any holidays. This means that the so called holiday rule (.is domains never deleted on holidays) will also be abandoned.
The third reason for this change, and perhaps the most important one, is to increase automation and enabling ISNIC to maintain stable registration and renewal fees in spite of cost increases.