String topology conjecture for closed oriented manifolds

Let $M$ be a closed oriented manifold of dimension $n$, and let \H_{\mathrm{dR}} be its de Rham cohomology. Let \DBCyc\,\H_{\mathrm{dR}}[2-n] denote a suitable shifted cyclic cochain complex. String topology conjecture. There exists an $\IBLInfty$-structure on a suitable version of \DBCyc\,\H_{\mathrm{dR}}[2-n] whose homology is the cyclic cohomology of the de Rham complex of $M$. The conjecture is meant to provide an algebraic chain model for string topology; the source gives no resolution.