Is email a legally accepted and valid mode of communications for sending any legal notice or letter to customer or supplier

At present, the legal notice served through email is also considered as sufficient service of legal notice. The legal notice can be served to the last known address only hence it is not the problem of the lawyer to not to send you the notice to your new address. you will need to have proof that the email was sent and the recipient read the email. If the recipient has admitted to receiving the email, or if he or she responded to it, this may serve as an official notice, but not in all circumstances. 

The legal notice served through email is considered as sufficient service of legal notice. if the recipient have accepted that it is his/her email id. it means deemed to be received. it can prove by cross examination.

E-mail is just like any other electronic records and it has to be prove accordinly under the appropriate laws, otherwise it can not be admmissible as evidence. It is alo important as to whether you are the sender of the e-mail or the recipient of the mail.