In some cases, it may be possible to pay an official fee “early”, before 1 April 2022, at the lower rate.
For example, it may be sensible to file a European regional phase application (based on an international (PCT) application) “early”, before 1 April 2022, so as to avoid the fee increase. (Note that it is not necessary also to request “early processing”). The “normal” deadline for entering the European regional phase is 31 months from the earliest priority date, or, if priority is not claimed, from the international application date. It is common to act a few weeks or months before that deadline, and so by also acting before 1 April 2022, the increased official fees may be avoided.
EPO announces fee increases from 1 April 2022 (mewburn.com)
Applicants can save money by paying fees early, ahead of the 1 April 2022 fee increase date, even if the official deadline for paying the fee is not until later in the year. Some fee payments, such as requesting examination and paying renewal fees, can be performed several months ahead of the official deadline so applicants may find it worthwhile to review their patent portfolios to check what fee payments are due over the next few months. A key example that could result in significant savings is entering the European regional phase early (i.e. before 1 April 2022). By doing this, applicants can save up to €115 per application (around 3% of the official fees). Although this would involve attending to the formalities to enter the European regional phase early, it would not bring forward other costs associated with the application as there is no need to request early processing of the application should an applicant choose this option.
EPO fee increases from 1 April 2022: What you need to know - Mathys & Squire LLP (mathys-squire.com)