For now downgrading to `python3-matrix-common` 1.2.1-1~bpo11+1 worked in
booting `matrix-synapse`
- Bug#1021435: python3-matrix-common: matrix-synapse not star... Sahil Dhiman
- Bug#1021435: python3-matrix-common: matrix-synapse not... Sahil Dhiman
- Bug#1021435: Info received (python3-matrix-common: mat... Sahil Dhiman
- Bug#1021435: python3-matrix-common: matrix-synapse not... Nilesh Patra
- Bug#1021435: python3-matrix-common: matrix-synapse... Andrej Shadura