use NopCommerce 3.90
Besides the most common point - bug fixes, should point your attention of two more points, as your country is part of EU. Version of software should be chosen in regards of current law requirements.
- 3.90 does not support GDPR.
- recently new requirement for payments was applied. Old versions of payments may not support it.
Of course, you may implement solution from version of 4.20, but this mean time and/or money.