Microsoft partner Network provides you the benefit of having access to OEM software and Training resources from Microsoft to support your customers exclusively and take their business to the next level and this requires your company to get registered for membership and also you require to renew this MPN membership every year.
More information is available in the below link on MPN
Also read this below blog post on upcoming changes
Changes to Expect in Microsoft Partner Network
This blog post is taken from O365 command website which talks about the changes that are going to occur in Microsoft Partner program by Microsoft