diff --git a/framing_format.txt b/framing_format.txt
index 9764e83..9d98706 100644
--- a/framing_format.txt
+++ b/framing_format.txt
@@ -1,9 +1,9 @@
 Snappy framing format description
-Last revised: 2013-10-25
+Last revised: 2022-05-23
 
 This format decribes a framing format for Snappy, allowing compressing to
 files or streams that can then more easily be decompressed without having
-to hold the entire stream in memory. It also provides data checksums to
+to hold the entire stream in memory. It also provides optional data checksums to
 help verify integrity. It does not provide metadata checksums, so it does
 not protect against e.g. all forms of truncations.
 
@@ -106,7 +106,21 @@ no more than 65536 data bytes, so the maximum legal chunk length with the
 checksum is 65540.
 
 
-4.4. Padding (chunk type 0xfe)
+4.4. Compressed data without checksum (chunk type 0x02)
+
+This chunk type is identical to "Compressed data" (type 0x00) except that
+the compressed data is _not_ preceded by a checksum.  The same size and
+other limitations apply.
+
+
+4.5. Uncompressed data without checksum (chunk type 0x03)
+
+This chunk type is identical to "Uncompressed data" (type 0x01) except that
+the data is _not_ preceded by a checksum.  The same size and other
+limitations apply.
+
+
+4.6. Padding (chunk type 0xfe)
 
 Padding chunks allow a compressor to increase the size of the data stream
 so that it complies with external demands, e.g. that the total number of
@@ -117,7 +131,7 @@ should be zero, but decompressors must not try to interpret or verify the
 padding data in any way.
 
 
-4.5. Reserved unskippable chunks (chunk types 0x02-0x7f)
+4.7. Reserved unskippable chunks (chunk types 0x04-0x7f)
 
 These are reserved for future expansion. A decoder that sees such a chunk
 should immediately return an error, as it must assume it cannot decode the
@@ -126,7 +140,7 @@ stream correctly.
 Future versions of this specification may define meanings for these chunks.
 
 
-4.6. Reserved skippable chunks (chunk types 0x80-0xfd)
+4.8. Reserved skippable chunks (chunk types 0x80-0xfd)
 
 These are also reserved for future expansion, but unlike the chunks
 described in 4.5, a decoder seeing these must skip them and continue