Hello,
I have an issue when I try to use kamailio 5.1 with usrloc and db_mongdb modules.
When I try to start kamailio, I get the following error:

0(22216) DEBUG: <core> [db.c:314]: db_do_init2(): connection 0x7f735b5c4100 not found in pool
 0(22216) DEBUG: db_mongodb [mongodb_connection.c:55]: db_mongodb_new_connection(): connection open to: mongodb://10.0.12.149,10.0.12.150,10.0.12.151/kamailio?replicaSet=sre_location&slaveOk=true&readPreference=primaryPreferred
 0(22216) DEBUG: db_mongodb [mongodb_dbase.c:864]: db_mongodb_query(): query to collection [version]
 0(22216) DEBUG: db_mongodb [mongodb_dbase.c:898]: db_mongodb_query(): query filter: { "table_name" : "location" }
 0(22216) DEBUG: db_mongodb [mongodb_dbase.c:917]: db_mongodb_query(): columns filter: { "table_version" : 1 }
 0(22216) DEBUG: <core> [db_res.c:120]: db_new_result(): allocate 56 bytes for result set at 0x7f735b5c4450
 0(22216) DEBUG: db_mongodb [mongodb_dbase.c:746]: db_mongodb_store_result(): no result from mongodb
 0(22216) DEBUG: <core> [db.c:404]: db_table_version(): no row for table location found
 0(22216) ERROR: <core> [db.c:450]: db_check_table_version(): invalid version 0 for table location found, expected 9 (check table structure and table "version")
 0(22216) ERROR: usrloc [dlist.c:659]: register_udomain(): error during table version check.
 0(22216) DEBUG: <core> [db_pool.c:100]: pool_remove(): removing connection from the pool
 0(22216) ERROR: registrar [registrar.c:651]: domain_fixup(): failed to register domain
 0(22216) ERROR: <core> [core/route.c:1154]: fix_actions(): fixing failed (code=-1) at cfg:/usr/local/kamailio-5.1/etc/kamailio/kamailio.cfg:660
 0(22216) ERROR: <core> [core/rvalue.c:3860]: fix_rval_expr(): failure in cfg at line: 660 col: 22
 0(22216) ERROR: <core> [core/rvalue.c:3860]: fix_rval_expr(): failure in cfg at line: 660 col: 22
 0(22216) ERROR: <core> [core/route.c:1154]: fix_actions(): fixing failed (code=-1) at cfg:/usr/local/kamailio-5.1/etc/kamailio/kamailio.cfg:663
ERROR: error -1 while trying to fix configuration
 0(22216) DEBUG: tm [t_funcs.c:85]: tm_shutdown(): start
 0(22216) DEBUG: tm [t_funcs.c:88]: tm_shutdown(): emptying hash table
 0(22216) DEBUG: tm [t_funcs.c:90]: tm_shutdown(): removing semaphores
 0(22216) DEBUG: tm [t_funcs.c:92]: tm_shutdown(): destroying tmcb lists
 0(22216) DEBUG: tm [t_funcs.c:95]: tm_shutdown(): done
 0(22216) INFO: <core> [core/sctp_core.c:53]: sctp_core_destroy(): SCTP API not initialized
 0(22216) DEBUG: <core> [core/mem/shm.c:261]: shm_destroy_manager(): destroying memory manager: q_malloc
 0(22216) DEBUG: <core> [core/mem/q_malloc.c:1165]: qm_shm_lock_destroy(): destroying the shared memory lock
 0(22216) DEBUG: <core> [core/mem/pkg.c:91]: pkg_destroy_manager(): destroying memory manager: q_malloc


In mongoDB, I have the collection "version" in the db kamailio, and the entries needed for usrloc (location and location_attrs):
sre_location:PRIMARY> use kamailio
switched to db kamailio
sre_location:PRIMARY> db.getCollection("version").find()
{ "_id" : ObjectId("5a8ec43c601b262bef82a595"), "table_name" : "location", "table_version" : 9 }
{ "_id" : ObjectId("5a8edb72a3ec40427577b8d0"), "table_name" : "location_attrs", "table_version" : 1 }


And logs in mongo show the following info when kamailio starts:

2018-02-22T17:13:02.604+0100 I NETWORK  [conn90] received client metadata from 10.0.12.180:56320 conn: { driver: { name: "mongoc", version: "1.9.2" }, os: { type: "Linux", name: "CentOS", version: "6.9 (Final)", architecture: "x86_64" }, platform: "cfg=0x1563000 posix=200809 CC=GCC 4.4.7 20120313 (Red Hat 4.4.7-18) CFLAGS="" LDFLAGS=""" }
2018-02-22T17:13:02.604+0100 I COMMAND  [conn90] command admin.$cmd command: isMaster { isMaster: 1, client: { driver: { name: "mongoc", version: "1.9.2" }, os: { type: "Linux", name: "CentOS", version: "6.9 (Final)", architecture: "x86_64" }, platform: "cfg=0x1563000 posix=200809 CC=GCC 4.4.7 20120313 (Red Hat 4.4.7-18) CFLAGS="" LDFLAGS=""" }, compression: [], $readPreference: { mode: "secondaryPreferred" }, $db: "admin" } numYields:0 reslen:716 locks:{} protocol:op_query 0ms
2018-02-22T17:13:02.604+0100 I COMMAND  [conn90] command kamailio.$cmd command: find { find: "version", filter: { table_name: "location" }, table_version: 1, $db: "kamailio", $readPreference: { mode: "primaryPreferred" }, $clusterTime: { clusterTime: Timestamp(1519315979, 1), signature: { hash: BinData(0, 0000000000000000000000000000000000000000), keyId: 0 } } } numYields:0 reslen:531 locks:{} protocol:op_msg 0ms
2018-02-22T17:13:02.605+0100 I NETWORK  [conn90] end connection 10.0.12.180:56320 (9 connections now open)

I probably miss something: it is not clear to me why kamailio is not able to retrieve the value of table_version for the table_name location. Any idea would be very welcome !

I use mongo-c-driver 1.9.2 and mongodb 3.6

Thank you.
Stephane