Clients since 2.6.18 DO NOT need any patches.
PATCH SERIES FOR SERVER KERNELS:
-3.10-rhel7.6.series 3.10.0-957.27.2.el7 (RHEL 7.6)
-3.10-rhel7.7.series 3.10.0-1062.18.1.el7 (RHEL 7.7)
-3.10-rhel7.8.series 3.10.0-1127.19.1.el7 (RHEL 7.8)
-4.18-rhel8.series 4.18.0-80.11.2.el8 (RHEL 8.0)
-4.18-rhel8.1.series 4.18.0-147.8.1.el8 (RHEL 8.1)
-4.18-rhel8.2.series 4.18.0-193.6.3.el8 (RHEL 8.2)
+3.10-rhel7.9.series 3.10.0-1160.88.1.el7 (RHEL 7.9)
+4.18-rhel8.4.series 4.18.0-305.25.1.el8 (RHEL 8.4)
+4.18-rhel8.5.series 4.18.0-348.23.1.el8 (RHEL 8.5)
+4.18-rhel8.6.series 4.18.0-372.32.1.el8 (RHEL 8.6)
+4.18-rhel8.7.series 4.18.0-425.10.1.el8 (RHEL 8.7)
+4.18-rhel8.8.series 4.18.0-477.27.1.el8 (RHEL 8.8)
+4.18-rhel8.9.series 4.18.0-513.18.1.el8 (RHEL 8.9)
+5.14-rhel9.1.series 5.14.0-162.23.1.el9 (RHEL 9.1)
+5.14-rhel9.2.series 5.14.0-284.30.1.el9 (RHEL 9.2)
+5.14-rhel9.3.series 5.14.0-362.18.1.el9 (RHEL 9.3)
See lustre/ChangeLog for supported client kernel versions.