opencart2.x - Vendor systems returned INVALID or ERROR in response to notification POST - Sagepay Server -

ive built 2 websites using opencart 2 (many more on opencart 1) , both setup take sagepay server payments, come light both sites sagepay payments failing when sagepay tries talk opencart give green light. means no failure email notification sent store owner, , sale cancelled @ sagepay? can imagine both store owners not happy. contacted sagepay see happening , told me payments failing below error, far sagepay concerned payments had passed tests, because calling website not send correct response sagepay, had cancel transactions!

looking @ how sagepay works, seams sagepay returns autorisation opencart , opencart has whether going accept payment based upon being sent, , seams opencart 2 failing respond correctly?

is yet oc2 bug?

has come across , how put right

one site on oc 2.0.2.0 , other 1 2.0.3.1 setup correctly in payment module , ip address logged sagepay etc.., problem after payment authorisation.

transaction completed vendor systems returned invalid or error in response notification post. transaction cancelled vendor.

this big problem, , not sure how go fixing this, opencart 2 meant able take sagepay payments out of box, once few settings added in admin section, seams not setup correctly so.. cant believe no 1 else has come across this?

i used built in sage pay debug option told me md5 hash mismatch, after further digging , reading official sage pay server docs, there notice in bold red, stating ensure vendor name supplied in lower case, mine in title case in admin section. looks creator of opencart 2 has on looked this, used php`s strtolower function before md5 comparison in sagepay_server.php controller file convert vendor name lowercase. of course avoided entering vendor name in sage pay server admin section lower case. seeing there no note when entering this, opencart should convert vendor name lowercase have done ensure no possibility of error.