Up to A.Y. 2013-14 Partnership Firms to whom provisions of section 44AB (i.e. those Under Tax Audit) were required to furnish the return for assessment year 2011-12 and subsequent assessment years electronically under digital signature but the Partnership firms to whom Provisions of section 44AB were not applicable they were allowed to furnish the ITR-5 in any of the following mode :-

(i) furnishing the return in a paper form;
(ii) furnishing the return electronically under digital signature;
(iii) transmitting the data in the return electronically and thereafter submitting the verification of the return in Form ITR-V;
But with amendment in Rule 12 of Income Tax Rules 1962 vide Notification No. 24/2014 dated 01.04.2014 Filing Provisions as applicable from A.Y. 2014-15 in respect of ITR-5 are as follows :-
1. Partnership Firm who are required to get Audited Under Section 44AB can file ITR 5return only electronically under digital signature.
2. Partnership Firm who are required to get Audited Under Section 44AB can sumit the return in any of the following mode :-
(i) furnishing the return electronically under digital signature;
(ii) transmitting the data in the return electronically and thereafter submitting the verification of the return in Form ITR-V;
Relevant Extract of Revised Rule 12 is as follows :-

(3) The return of income referred to in sub-rule (1) may be furnished in any of the following manners, namely:—
(i) furnishing the return in a paper form;
(ii) furnishing the return electronically under digital signature;
(iii) transmitting the data in the return electronically and thereafter submitting the verification of the return in Form ITR-V;
(iv) furnishing a bar-coded return in a paper form:
Provided that—
(aaa) a firm required to furnish the return in Form ITR-5 or an individual or Hindu Undivided Family (HUF) required to furnish the return in Form ITR-4 and to whom provisions of section 44AB are applicable, shall furnish the return for assessment year 2011-12 and subsequent assessment years in the manner specified in clause (ii);
(aab) ………….
(aac) a person required to furnish the return in Form ITR-5, other than a firm to which clause (aaa) is applicable, shall furnish the return for the assessment year 2014-15 and subsequent assessment years in the manner specified in clause (ii) or clause (iii);