Before revision:  In the offline setting , the current best approximation ratio for pairwise spanners with uniform lengths and directed Steiner forests with uniform costs are both O(n^{ 3 / 5 + \epsilon}), due to Chlamtac, Dinitz, Kortsarz, and Laekhanukit (TALG 2020).
After revision:  In the offline setting , the current best approximation ratio with uniform costs is O(n^{ 3 / 5 + \epsilon}), due to Chlamtac, Dinitz, Kortsarz, and Laekhanukit (TALG 2020).