diff --git a/CHANGELOG.md b/CHANGELOG.md
index 866a4c5..871effd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,8 @@
 # Changelog
 
+## [0.2.6] - Unreleased
+- Added `KY` and `MM` to valid prefixes
+
 ## [0.2.5] - 2022-04-10
 - Fixed missing `jcs` dependency
 - Added SubType `NONE` to MT.ISCC to distinquish from SUM
diff --git a/docs/changelog.md b/docs/changelog.md
index 7ac05dd..871effd 100644
--- a/docs/changelog.md
+++ b/docs/changelog.md
@@ -1,6 +1,9 @@
 # Changelog
 
-## [0.2.5] - Unreleased
+## [0.2.6] - Unreleased
+- Added `KY` and `MM` to valid prefixes
+
+## [0.2.5] - 2022-04-10
 - Fixed missing `jcs` dependency
 - Added SubType `NONE` to MT.ISCC to distinquish from SUM
 - Added support for deterministic generation of random ISCC-CODEs
diff --git a/iscc_core/codec.py b/iscc_core/codec.py
index 7100e03..cc6a48d 100644
--- a/iscc_core/codec.py
+++ b/iscc_core/codec.py
@@ -536,9 +536,11 @@ def iscc_validate(iscc, strict=True):
         "KM",
         "KQ",
         "KU",
+        "KY",
         "MA",
         "ME",
         "MI",
+        "MM",
         "OA",
     }
     cleaned = iscc_clean(iscc)
diff --git a/tests/build_valid_prefixes.py b/tests/build_valid_prefixes.py
index 53548e3..6805e6d 100644
--- a/tests/build_valid_prefixes.py
+++ b/tests/build_valid_prefixes.py
@@ -21,7 +21,9 @@ def build_valid_prefixes():
         for stype in stype_for_mtype[mtype]:
             digest = ic.encode_header(mtype, stype, 0, 0)
             base = ic.encode_base32(digest)
-            prefixes.add(base[:2])
+            prefix = base[:2]
+            prefixes.add(prefix)
+            print(f"{prefix} -> {ic.MT(mtype).name}-{stype.name}")
 
     return sorted(list(prefixes))
 
diff --git a/tests/test_codec.py b/tests/test_codec.py
index 2357c10..d754803 100644
--- a/tests/test_codec.py
+++ b/tests/test_codec.py
@@ -496,6 +496,10 @@ def test_codec_validate_header_prefix():
         ic.iscc_validate(invalid)
 
 
+def test_codec_validate_iscc_id():
+    assert ic.iscc_validate("ISCC:MMAMRVPW22XVU4FR", strict=False) is True
+
+
 def test_decode_iscc():
     assert ic.iscc_decode("AAAQCAAAAABAAAAA") == (0, 0, 0, 1, b"\x01\x00\x00\x00\x02\x00\x00\x00")