It's looking like after months of positional warfare, the Ukrainian front may start moving again.
Putin did some 'holiday ceasefire' drama with the Ukrainians, which was refused by them. Russian forces went on ceasefire on Jan 6th.
However, Wagner PMC did not follow the ceasefire and attacked Soledar 1/6 in a planned operation.
They took the city and achieved a breakthrough in the Zelensky line about 2 days ago. The city of Bakhmut, the biggest pillar of the line has 1 out of 2 major supply roads threatened. Russian paratroops have been attacking to cut off highway M03 to Siversk, one of the two major supply roads feeding the Bakhmut garrison. In the South, Wagner PMC is attacking towards highway T054.
If both ground communications fall, the large Ukrainian garrison will be starved of supplies and begin to cannibalize, and eventually forced to withdraw.
The head of the DPR claimed that the Russian command will be moving 'serious forces' to exploit the situation. If that is the case the Zelensky line might be seriously contested. If not this crisis for Ukraine may be just temporary and we will have to wait for more months until the second invasion of Ukraine.
If Bakhmut falls, Siversk will be under operational encirclement from the South. The Russian reserves in the Svatove-Kremmina axis could launch an offensive operation and re-take Lyman. Siversk would then be encircled from the North and be in a pocket. Then they could be squeezed until they withdraw, and the front straightens up.
After the fall of Lyman, Siversk, and Bakhmut the Russians would be facing the final fortified defense line of the Donbass.