Rudder

When trying to upgrade from Rudder 2.3 to 2.4 on a squeeze, aptitude terminate with error:

etting up rudder-inventory-ldap (2.4.0~beta1-squeeze0) ...
Stopping enhanced syslogd: rsyslogd.
Starting enhanced syslogd: rsyslogd.
slapd[7458]: [INFO] Using /etc/default/slapd for configuration
slapd[7463]: [INFO] Halting OpenLDAP...
slapd[7464]: [INFO] can't read PID file, to stop slapd try: /etc/init.d/slapd forcestop
slapd[7465]: [INFO] Halting OpenLDAP replication...
slapd[7466]: [INFO] no replica found in configuration, aborting stopping slurpd
slapd[7467]: [INFO] Launching OpenLDAP configuration test...
slapd[7469]: [OK] OpenLDAP configuration test successful
slapd[7470]: [INFO] Launching OpenLDAP replication...
slapd[7471]: [INFO] no replica found in configuration, aborting lauching slurpd
slapd[7472]: [INFO] no db_recover done
slapd[7473]: [INFO] Launching OpenLDAP...
slapd[7474]: [OK] file descriptor limit set to 1024
slapd[7478]: [ALERT] no PID file for slapd
invoke-rc.d: initscript slapd, action "restart" failed.
dpkg: error processing rudder-inventory-ldap (--configure):
 subprocess installed post-installation script returned error exit status 1
configured to not write apport reports
                                      Errors were encountered while processing:
 rudder-inventory-ldap
E: Sub-process /usr/bin/dpkg returned an error code (1)

If we check /var/log/rudder/ldap/slapd.log:

[...]
ul  6 17:46:59 squeezedev slapd[4729]: bdb(cn=rudder-configuration): Program version 4.8 doesn't match environment version 4.6
Jul  6 17:46:59 squeezedev slapd[4729]: hdb_db_open: database "cn=rudder-configuration" cannot be opened, err -30971. Restore from backup!
Jul  6 17:46:59 squeezedev slapd[4729]: bdb(cn=rudder-configuration): txn_checkpoint interface requires an environment configured for the transaction subsystem
Jul  6 17:46:59 squeezedev slapd[4729]: bdb_db_close: database "cn=rudder-configuration": txn_checkpoint failed: Invalid argument (22).
Jul  6 17:46:59 squeezedev slapd[4729]: backend_startup_one (type=hdb, suffix="cn=rudder-configuration"): bi_db_open failed! (-30971)
Jul  6 17:46:59 squeezedev slapd[4729]: bdb_db_close: database "cn=rudder-configuration": alock_close failed
Jul  6 17:46:59 squeezedev slapd[4729]: slapd stopped.
[...]