Rso
“lubavitch rebbe had smicho from the Rogatchover Gaon. And they also corresponded. ”
In regards to ‘correspondence’ I don’t know what difference it makes, anyone familiar with the Rogatchovers works knows that he “corresponded” with anyone who wrote, (especially f you were a decendent of the Alter Rebbe – as he was Chabad, ,, though of the Kapuster, obviously he didn’t go for the seven does) as long as it fitted into his postcard size reply page.
However, if you would to say the “titles” addressed were somehow on the high caliber, then that would be something, knowing the Rogatchover… And I don’t think that is the case…