OCLC #8614974, Boston review (Cambridge, Mass. : 1982), has a 515 note "Last issue with the sequential designation of Volume ..., number ... was Volume 41, number 4 (July/August 2016). In 2017, the sequential designation changes to Forum ..."  As such it seems to treat "Forum" as a caption in new numbering pattern; for example, the 588 reads, "Latest issue consulted: Forum 2 (2017)." 

OCLC #971252200, Forum (Cambridge, Massachusetts), on the other hand treats this as though it is a  wholly new publication and not a continuation of Boston Reivew.

To my mind, it seems as though this new format and title should be treated as a "continues in part title" with a 245 of "Boston review. Forum."  The remainder of what was previously the Boston Review in print now appears to only be continued online.

Thanks,

Chris