Release notes for 8.15.4 (#16611)

Co-authored-by: Kaise Cheng <[email protected]>
Co-authored-by: Karen Metts <[email protected]>

docs/static/releasenotes.asciidoc

@@ -3,6 +3,7 @@
 
 This section summarizes the changes in the following releases:
 
+* <<logstash-8-15-4,Logstash 8.15.4>>
 * <<logstash-8-15-3,Logstash 8.15.3>>
 * <<logstash-8-15-2,Logstash 8.15.2>>
 * <<logstash-8-15-1,Logstash 8.15.1>>
@@ -68,6 +69,39 @@ This section summarizes the changes in the following releases:
 * <<logstash-8-0-0-alpha1,Logstash 8.0.0-alpha1>>
 
 
+[[logstash-8-15-4]]
+=== Logstash 8.15.4 Release Notes
+
+[[notable-8.15.4]]
+==== Notable issues fixed
+
+* Fixed an issue where Logstash could not consume lines correctly when a codec with a delimiter is in use and the input buffer becomes full https://github.com/elastic/logstash/pull/16482[#16482]
+
+[[dependencies-8.15.4]]
+==== Updates to dependencies
+
+* Updated JRuby to 9.4.9.0 https://github.com/elastic/logstash/pull/16638[#16638]
+
+[[plugins-8.15.4]]
+==== Plugins
+
+*Cef Codec - 6.2.8*
+
+* [DOC] Added `raw_data_field` to docs https://github.com/logstash-plugins/logstash-codec-cef/pull/105[#105]
+
+*Elastic_integration Filter - 0.1.15*
+
+* Fixed the connection failure where SSL verification mode is disabled over SSL connection https://github.com/elastic/logstash-filter-elastic_integration/pull/165[#165]
+
+*Geoip Filter - 7.3.1*
+
+* Fixed issue causing pipelines to crash during lookup when a database has custom fields https://github.com/logstash-plugins/logstash-filter-geoip/pull/225[#225]
+
+*Tcp Input - 6.4.3*
+
+* Updated dependencies https://github.com/logstash-plugins/logstash-input-tcp/pull/224[#224]
+
+
 [[logstash-8-15-3]]
 === Logstash 8.15.3 Release Notes