We report an updated measurement of the CP-violating phase, ϕ J/ψϕ s, and the decay-width difference for the two mass eigenstates, ΔΓ s, from the flavor-tagged decay B 0 s →J/ψϕ. The data sample corresponds to an integrated luminosity of 8.0 fb−1 accumulated with the D0 detector using pp¯ collisions at √s =1.96 TeV produced at the Fermilab Tevatron collider. The 68% Bayesian credibility intervals, including systematic uncertainties, are ΔΓ s=0.163 +0.065 −0.064 ps−1 and ϕ J/ψϕ s =−0.55 +0.38 −0.36. The p-value for the Standard Model point is 29.8%.