Absolutely not. There will be no adjustments to entry fees for events if the entry fee changes. Users cannot claim for refund/repayment if the entry fee changes.
For example, if a certain user pays 20 taka for the entry fee and the entry fee changes to 30 taka afterward. He does not have to pay an extra 10 taka for the change in fee. On the other hand, if a user pays 20 taka entry fee for another event and the entry fee changes to 10 taka, therefore he/she will not be refunded with 10 taka. Keeping the rules fair in both cases.