Can a partnership firm opt for presumptive taxation u/s 44ad if it never opted for it in prev 10 yrs

Yes, Partnership firm can opt for sec. 44 AD of IT act afresh, without any restrictions of previous filing of ITR 5.

Thanks for the reply. 

In ITR 4 Sugam there is no provision to show individual Partner's Capital, Interest and remuneration. Or are these not required in ITR 4. 
Can I still use ITR 3 for both partners like previous years.

Yes, that is not required in ITR4, for firm.

For individual partners ITR3 need to be filed.

Thanks Sir. 

In Presumptive Taxation u/s 44AD there is no need to maintain books of accounts u/s 44AA. 
Will it apply to the partners as well. Do they need to maintain books of accounts u/s 44AA  or it is not required since the firm is not required to do so.