Add Fleet & Agent 8.15.1 Release Notes

docs/en/ingest-management/release-notes/release-notes-8.15.asciidoc

@@ -21,6 +21,26 @@ Also see:
 * {kibana-ref}/release-notes.html[{kib} release notes]
 * {beats-ref}/release-notes.html[{beats} release notes]
 
+// begin 8.15.1 relnotes
+
+[[release-notes-8.15.1]]
+== {fleet} and {agent} 8.15.1
+
+Review important information about the {fleet} and {agent} 8.15.1 release.
+
+[discrete]
+[[bug-fixes-8.15.1]]
+=== Bug fixes
+
+// {fleet}::
+
+{agent}::
+* Fix the Debian packaging to properly copy the `state.enc` and `state.yml` files to the new version of the {agent}. {agent-pull}5260[#5260] {agent-issue}5101[#5101]
+* Switch from wall clock to montonic clocks for component check-in calculation. {agent-pull}5284[#5284] {agent-issue}5277[#5277]
+* For a failed installation return a `nil` error instead of `syscall.Errno(0)` which indicates a successful operation on Windows. {agent-pull}5317[#5317] {agent-issue}4496[#4496]
+
+// end 8.15.1 relnotes
+
 // begin 8.15.0 relnotes
 
 [[release-notes-8.15.0]]