SURT8000RMXLI+ SURT192RMXLBP2 - strange beaviour after input power loss - output power turned off

[Anonymous user]

Two weeks ago we had a strange behaviour of our UPS:

All self tests are running smooth, but suddenly the system reports (translated from German language):

UPS output power turned off due to low battery condition. This is reported at 4:32:11 pm.

at 4:36:44 RFC1628 MIB alarm entry removed.

again at 4:39:52 On battery power due to input power problem and at 4:40:08 the clearing messages are reported.

Last weekend I have performed a calibration and the reported remaining runtime is 54minutes with 10% load.

Is there anything I could do, firmware or software upgrade? The System was installed in 2011.

Smart-UPS RT 8000 RM XL
RACK
IS++++++++++
477.18.W
01/24/11

Name: sumx
Version: v5.1.7
Datum: Dec 1 2011
Uhrzeit: 13:01:45
APC OS (AOS)

Name: aos
Version: v5.1.7
Datum: Nov 22 2011
Uhrzeit: 09:53:57
APC-Boot-Monitor

Name: bootmon
Version: v1.0.2
Datum: Jan 21 2010
Uhrzeit: 13:35:57

As I have found on the APC website a newer AOS and a newer PCNS version I wonder if we should update the UPS. Is this recommended and were I could find the release notes matching to a newer firmware?

Thank you for a helpful answer.