Both Legacy and Free 100 will be going entirely - at least, in terms of enrolling new devices. If you want Systems Manager capabilites for new devices after 7th Feb, you will need to purchase the appropriate quantity of licences. These can be ordered using a SKU of the form LIC-SME-xYR where x = the number of years (1, 3 or 5). The quantity is determined by the number of devices you wish to manage using Systems Manager.
https://documentation.meraki.com/SM/Other_Topics/Meraki_SM_Legacy_and_Free_100_Retirement_FAQ
As per this document, Meraki support for both Legacy and Free also end on this date.
