There are several possible options for migration between two Premium plans before the expiration of the current plan with immediate effect:
Example:
Albert has a monthly subscription to the Silver tier of Locus Map. This subscription costs him 1 € per month, and it renews on the first of the month.
On April 15, Albert chose to upgrade to the annual version of the Gold subscription, which costs 24 € per year.
Albert’s Silver subscription ends immediately. Since he paid for a full month (April 1-30) but upgraded halfway through the subscription period, half of a month’s subscription (0.5 €) is applied to his new subscription. However, since that new subscription costs 24 € per year, the 0.5 € credit balance pays for only one week (April 16-23), so on April 24, he is charged 24 € for a new subscription and another 24 € on April 24 of each year following.
Other options for the transfer of the Premium plan are possible only after the expiration of the full period of the first plan.