Upgrade ELK stack from 7.13 to 7.15
I checked /_cat/indices/.kibana?v*
health status index uuid pri rep docs.count docs.deleted store.size pri.store.size
green open .kibana-event-log-7.15.2-000001 6TDXTgf8RwGjVH3LMJcOCA 1 1 57 0 195.2kb 97.5kb
green open .kibana-event-log-7.12.0-000004 jCatWqqqRJmUplxQ1hgD9w 1 1 0 0 416b 208b
green open .kibana-event-log-7.12.0-000005 U76-rUAARaGC_DfcCpRu6Q 1 1 0 0 416b 208b
green open .kibana_security_session_1 IAslrfK5Sc6AcFbAoyu_3g 1 1 1 0 11kb 5.5kb
green open .kibana-event-log-7.12.0-000006 amxJywUMSPib_-J0ExE6nA 1 1 0 0 416b 208b
green open .kibana_7.12.0_001 o5xRcvxgSsSztBNOCfIkJA 1 1 889 76 5.6mb 2.8mb
green open .kibana-event-log-7.12.0-000003 tqJa5UroT_qVl3yQuyAIEg 1 1 0 0 416b 208b
green open .kibana_task_manager_7.15.2_001 DGlfNTB8RIWdGErmzWWVfg 1 1 34 1994 733.9kb 331.7kb
green open .kibana_7.13.2_001 MBCEN4KvSrW4WUmNXLAvHw 1 1 1841 490 8.3mb 4mb
green open .kibana-event-log-7.13.2-000002 9AzRupr4RRSOHvGQI2ESWA 1 1 11555241 0 1.3gb 671.2mb
green open .kibana-event-log-7.13.2-000003 j-1akr2xRpCcMevd4DTi6A 1 1 12541998 0 1.4gb 720.2mb
green open .kibana-event-log-7.13.2-000004 4nUblHNZTuW09FrpyhIBoA 1 1 1031364 0 130.3mb 65.1mb
green open .kibana-event-log-7.13.2-000005 cgOKFRa5SAWYXoGPfv8Eaw 1 1 702537 0 86.7mb 43.4mb
green open .kibana_task_manager_7.13.2_001 TByrB3fUSTSfQnf1v5aGpQ 1 1 29 2144 650.1kb 381.1kb
green open .kibana_7.15.2_001 D2FpFf09Skq0Ww6rxvp6Bg 1 1 1848 2766 19.5mb 9.7mb
which .kibana
index i can delete safely without intrupting and dashboards or it can be deleted automatically.