diff --git a/rules/S5866/highlighting.adoc b/rules/S5866/highlighting.adoc
new file mode 100644
index 00000000000..f94093c540b
--- /dev/null
+++ b/rules/S5866/highlighting.adoc
@@ -0,0 +1,4 @@
+=== Highlighting
+
+The use of `Pattern.CASE_INSENTIVE` or the `i` in `(?i)` or `(?i:...)`
+
diff --git a/rules/S5866/java/highlighting.adoc b/rules/S5866/java/highlighting.adoc
deleted file mode 100644
index a4c34b9e2c1..00000000000
--- a/rules/S5866/java/highlighting.adoc
+++ /dev/null
@@ -1,4 +0,0 @@
-=== Highlighting
-
-The use of ``++Pattern.CASE_INSENTIVE++`` or the ``++i++`` in ``++(?i)++`` or ``++(?i:...)++``
-
diff --git a/rules/S5866/java/metadata.json b/rules/S5866/java/metadata.json
index 5a2eb9760e4..2c63c085104 100644
--- a/rules/S5866/java/metadata.json
+++ b/rules/S5866/java/metadata.json
@@ -1,27 +1,2 @@
 {
-  "title": "Case insensitive Unicode regular expressions should enable the “UNICODE_CASE” flag",
-  "type": "BUG",
-  "status": "ready",
-  "remediation": {
-    "func": "Constant\/Issue",
-    "constantCost": "3min"
-  },
-  "tags": [
-    "regex"
-  ],
-  "extra": {
-    "replacementRules": [
-
-    ],
-    "legacyKeys": [
-
-    ]
-  },
-  "defaultSeverity": "Major",
-  "ruleSpecification": "RSPEC-5866",
-  "sqKey": "S5866",
-  "scope": "All",
-  "defaultQualityProfiles": [
-    "Sonar way"
-  ]
 }
diff --git a/rules/S5866/java/rule.adoc b/rules/S5866/java/rule.adoc
index cc56eb02765..65438505429 100644
--- a/rules/S5866/java/rule.adoc
+++ b/rules/S5866/java/rule.adoc
@@ -33,8 +33,8 @@ ifdef::env-github,rspecator-view[]
 == Implementation Specification
 (visible only on this page)
 
-include::message.adoc[]
+include::../message.adoc[]
 
-include::highlighting.adoc[]
+include::../highlighting.adoc[]
 
 endif::env-github,rspecator-view[]
diff --git a/rules/S5866/kotlin/metadata.json b/rules/S5866/kotlin/metadata.json
new file mode 100644
index 00000000000..2c63c085104
--- /dev/null
+++ b/rules/S5866/kotlin/metadata.json
@@ -0,0 +1,2 @@
+{
+}
diff --git a/rules/S5866/kotlin/rule.adoc b/rules/S5866/kotlin/rule.adoc
new file mode 100644
index 00000000000..ea0af04473f
--- /dev/null
+++ b/rules/S5866/kotlin/rule.adoc
@@ -0,0 +1,40 @@
+Enabling case-insensitive matching using `(?i)` within a regex will only apply to characters in the ASCII range. To include characters outside of this range, use the `RegexOption.IGNORE_CASE` flag. Alternatively, you can use `(?iu)` or `(?iU)` within the regex instead.
+
+If not done, regular expressions involving non-ASCII letters will still handle those letters as being case sensitive.
+
+
+== Noncompliant Code Example
+
+----
+Regex("(?i)söme pättern")
+Regex("(?i:söme) pättern")
+
+"(?i)söme pättern".toRegex()
+"(?i:söme) pättern".toRegex()
+----
+
+
+== Compliant Solution
+
+----
+Regex("söme pättern", RegexOption.IGNORE_CASE)
+Regex("(?iu)söme pättern")
+Regex("(?iu:söme) pättern")
+
+"söme pättern".toRegex(RegexOption.IGNORE_CASE)
+"(?iu)söme pättern".toRegex()
+"(?iu:söme) pättern".toRegex()
+----
+
+
+ifdef::env-github,rspecator-view[]
+
+'''
+== Implementation Specification
+(visible only on this page)
+
+include::../message.adoc[]
+
+include::../highlighting.adoc[]
+
+endif::env-github,rspecator-view[]
diff --git a/rules/S5866/java/message.adoc b/rules/S5866/message.adoc
similarity index 100%
rename from rules/S5866/java/message.adoc
rename to rules/S5866/message.adoc
diff --git a/rules/S5866/metadata.json b/rules/S5866/metadata.json
index 2c63c085104..5a2eb9760e4 100644
--- a/rules/S5866/metadata.json
+++ b/rules/S5866/metadata.json
@@ -1,2 +1,27 @@
 {
+  "title": "Case insensitive Unicode regular expressions should enable the “UNICODE_CASE” flag",
+  "type": "BUG",
+  "status": "ready",
+  "remediation": {
+    "func": "Constant\/Issue",
+    "constantCost": "3min"
+  },
+  "tags": [
+    "regex"
+  ],
+  "extra": {
+    "replacementRules": [
+
+    ],
+    "legacyKeys": [
+
+    ]
+  },
+  "defaultSeverity": "Major",
+  "ruleSpecification": "RSPEC-5866",
+  "sqKey": "S5866",
+  "scope": "All",
+  "defaultQualityProfiles": [
+    "Sonar way"
+  ]
 }