Hi
I made an update of my RS from 3.4.1 to 3.6.4,
but application where not using newest driver yet,
so I was enforced to downgrade back
(acc to docu, I have chosen the newest 3.4.14 ).
Downgrade was not possible. Even with data removal (enforce "scratch-replication").
I constantly got error, about config.system.session collection :
018-04-25T17:21:01.319+0200 F REPL [repl writer worker 1] writer worker caught exception: 10156 cannot update system collection: config.system.sessions q: { _id: { id: BinData(4, 96E23194367D482B81B1D75B6423AFBD), uid: BinData(0, EEDC58CB4933CBA895757E2FD8275E869A732F964407D28FA4D462EE4FC5B046) } } u: { $set: { lastUse: new Date(1524669659199) } } on: { ts: Timestamp 1524669659000|10, t: 39, h: 6122200662662238595, v: 2, op: "u", ns: "config.system.sessions", o2: { _id: { id: BinData(4, 96E23194367D482B81B1D75B6423AFBD), uid: BinData(0, EEDC58CB4933CBA895757E2FD8275E869A732F964407D28FA4D462EE4FC5B046) } }, wall: new Date(1524669659197), o: { $set: { lastUse: new Date(1524669659199) } } } 2018-04-25T17:21:01.319+0200 I - [repl writer worker 1] Fatal assertion 16359 Location10156: cannot update system collection: config.system.sessions q: { _id: { id: BinData(4, 96E23194367D482B81B1D75B6423AFBD), uid: BinData(0, EEDC58CB4933CBA895757E2FD8275E869A732F964407D28FA4D462EE4FC5B046) } } u: { $set: { lastUse: new Date(1524669659199) } } at src/mongo/db/repl/sync_tail.cpp 1082 2018-04-25T17:21:01.319+0200 F REPL [repl writer worker 15] writer worker caught exception: 10156 cannot update system collection: config.system.sessions q: { _id: { id: BinData(4, F7749D80D99044C18AEC4F16DB0841A6), uid: BinData(0, 575CD72AF2368BDED794D83BD07BA14894021281F75D97BE815F1FE5D795D1E1) } } u: { $set: { lastUse: new Date(1524669659199) } } on: { ts: Timestamp 1524669659000|6, t: 39, h: 9214092136229990651, v: 2, op: "u", ns: "config.system.sessions", o2: { _id: { id: BinData(4, F7749D80D99044C18AEC4F16DB0841A6), uid: BinData(0, 575CD72AF2368BDED794D83BD07BA14894021281F75D97BE815F1FE5D795D1E1) } }, wall: new Date(1524669659197), o: { $set: { lastUse: new Date(1524669659199) } } } 2018-04-25T17:21:01.319+0200 I - [repl writer worker 1] ***aborting after fassert() failure
I have even tried to drop the collection and db config
but it was recreated.