The registration with serial keys was included to our app beginning from version 2.7 and higher. Both Standard and PRO version keys are usable for version 2.7 and higher. Only KSWEB 3.1 and higher is extendable to PRO version with PRO version key. Notice, that your serial key is bound to your Google account. In case of use KSWEB for business applications, one license is valid only on one device. For home use, your license is valid on all android devices with your Google account.
More information about KSWEB licensing offers for business applications is available here: BUSINESS OFFERS.