since 0.8.6.9 I tried to start 0.8.6.8 again to start staking again, now I get this error:
./Espers-qt: error while loading shared libraries: libboost_system.so.1.54.0: cannot open shared object file: No such file or directory
Espers qt-wallet broken on Linux

for now I will try to install new wallet on Windows but I would like to Linux
You probably updated libboost-system in the previous step. After updating libraries, you must recompile all programs that are linked against it.