The changes in expiration date for the subscriptions with N-month period

After a subscriptions with N-month period is renewed the new expiration date depends on the number of days in the month.

Let's consider an example of ordering and renewing a subscription with 1 month period.

1. A new subscription was created on 31.12.2016. The subscription period is 1 month, so the subscription expiration date is set on 31.01.2017. The subscription is available from 31.12.2016 to 31.01.2017 inclusive. The subscription period is 31 days.
2. After the subscription is renewed (manually or automatically), new expiration date is set according to the previous expiration date and the number of days in the month. There are 28 days in February, and new subscription period is from 01.02.2017 to 28.02.2017 inclusive. The subscription period is 28 days.
3. After the subscription is renewed, new expiration date is set. Since the previous expiration date was on 28.02.2017, new expiration date is set on 28.03.2017. The subscription period is from 01.03.2017 to 28.03.2017 inclusive. The subscription period is 28 days.