In his interview to VPK about a month ago General Igor Khvorov, the commander of the 37th Long-Range Army, described his vision for production of new aircraft (I was busy sorting out numbers and almost missed that bit).
As I understand, the plan is to complete the Tu-160 overhaul program, during which all currently deployed aircraft of this type will get new avionics. According to Khvorov, the program may take about 10-15 years, after which the industry would be ready to begin production of a new strategic bomber. The way Khvorov described it suggests that this will not be a completely new plane. He said that Tu-160 has about 75% of the features that the new aircraft will need and stressed the importance of avionics. Which is not unreasonable - it hardly makes sense to develop a new airframe (whether it makes sense to develop a new strategic bomber is also a legitimate question).
Tu-95MS is likely to stay in service for at least 10-15 more years, until the new aircraft is ready (assuming it will go ahead). They will also undergo an avionics upgrade, which will allow them to use conventional weapons (cruise missiles and gravity bombs). This modernization, however, will not be as deep as the one planned for Tu-160.