tilts_at_infinity_review.md

@@ -43,6 +43,10 @@ The evolution to infinity currently does not produce samples at infinity in alig
 
 I sign off on this code as merged to master in [this commit](https://git.ligo.org/lscsoft/pesummary/-/commit/7c7d174fc87191a31b1e69f73b97d4132e14ca15). NKJ-M, 20.7.2021
 
+### Signoff of update to using SpinTaylorT4 in the hybrid evolution
+
+Due to a bug found in SpinTaylorT5 (3PN spin-orbit terms in the phase were removed by accident when adding the 3PN spin-spin terms), it was necessary to change to using SpinTaylorT4 in the hybrid evolution for quick use to obtain the O3a-final and O3b catalogue results. I have checked the update in [this merge request](https://git.ligo.org/lscsoft/pesummary/-/merge_requests/613) both by code inspection and by some spot checks of the output of the tests linked in that merge request using a slight modification of the script below. I thus sign off on these changes. NKJ-M, 27.7.2021
+
 ### Comparison script
 ```
 # Check PESummary output of tilts at infinity