The case is Midland Funding, LLC v. Johnson. SCOTUSBlog describes the issues as:
(1) Whether the filing of an accurate proof of claim for an unextinguished time-barred debt in a bankruptcy proceeding violates the Fair Debt Collection Practices Act; and (2) whether the Bankruptcy Code, which governs the filing of proofs of claim in bankruptcy, precludes the application of the Fair Debt Collection Practices Act to the filing of an accurate proof of claim for an unextinguished time-barred debt.
Their coverage is here.