Raising Rent under new regulations

According to the new regulations “Landlords must give at least 30 days’ notice to tenants if they intend to raise the rent of a unit by more than 5 percent. The longer a tenant has been in place, the more notice a landlord must give of a large rent increase: 60 days’ notice for a tenancy or lease of one to two years, and 90 days’ notice to a tenant who has lived in a unit for at least two years or has a lease of at least that length.”

I have 3 units that have been in place for more than 2 years. I would like to increase the rents by about 7.5%. The units are not rent regulated or controlled, however, it’s my understanding that these notifications rules apply to ALL landlords.

I know that the reg’s where signed in June. Did they go into effect immediately?

If I wanted the effective date to be Jan 1, 2020, does that mean that the tenants need to be notified no later than Oct.1,2019? Will an email suffice as notification or does it need to be more official.