diff --git a/docs/src/flatten-unflatten.md b/docs/src/flatten-unflatten.md
index da0e817db..9706ddd1d 100644
--- a/docs/src/flatten-unflatten.md
+++ b/docs/src/flatten-unflatten.md
@@ -390,6 +390,10 @@ f.g  6
   }
 }
 ]
+mlr: field name "b." contains separator "." but cannot be auto-unflattened; treating as a literal string. Use --no-auto-unflatten to suppress this warning.
+mlr: field name ".c" contains separator "." but cannot be auto-unflattened; treating as a literal string. Use --no-auto-unflatten to suppress this warning.
+mlr: field name "." contains separator "." but cannot be auto-unflattened; treating as a literal string. Use --no-auto-unflatten to suppress this warning.
+mlr: field name "d..e" contains separator "." but cannot be auto-unflattened; treating as a literal string. Use --no-auto-unflatten to suppress this warning.
 </pre>
 
 ## Manual control
diff --git a/docs/src/manpage.md b/docs/src/manpage.md
index 9e21d522c..709a48d9c 100644
--- a/docs/src/manpage.md
+++ b/docs/src/manpage.md
@@ -48,7 +48,7 @@ This is simply a copy of what you should see on running `man mlr` at a command p
        insertion-ordered hash map.  This encompasses a variety of data
        formats, including but not limited to the familiar CSV, TSV, and JSON.
        (Miller can handle positionally-indexed data as a special case.) This
-       manpage documents mlr 6.18.0.
+       manpage documents mlr 6.18.1.
 
 1mEXAMPLES0m
        mlr --icsv --opprint cat example.csv
@@ -1920,8 +1920,13 @@ This is simply a copy of what you should see on running `man mlr` at a command p
        Usage: mlr sort-within-records [options]
        Outputs records sorted lexically ascending by keys.
        Options:
-       -r        Recursively sort subobjects/submaps, e.g. for JSON input.
-       -h|--help Show this message.
+       -f {names}   Sort only these keys; others preserve record order.
+       -r {regex}   Sort only keys matching this regex; others preserve record order.
+                    Example: -r '^[xy]' sorts keys starting with x or y.
+                    With no regex argument, -r recursively sorts subobjects/submaps
+                    (e.g. for JSON input), or combines with -f to treat names as regex.
+       -n           Sort field names naturally (e.g. 2 before 12). Combines with -f/-r.
+       -h|--help    Show this message.
 
    1msparsify0m
        Usage: mlr sparsify [options]
diff --git a/docs/src/manpage.txt b/docs/src/manpage.txt
index 72735e79a..ae5d678ff 100644
--- a/docs/src/manpage.txt
+++ b/docs/src/manpage.txt
@@ -27,7 +27,7 @@
        insertion-ordered hash map.  This encompasses a variety of data
        formats, including but not limited to the familiar CSV, TSV, and JSON.
        (Miller can handle positionally-indexed data as a special case.) This
-       manpage documents mlr 6.18.0.
+       manpage documents mlr 6.18.1.
 
 1mEXAMPLES0m
        mlr --icsv --opprint cat example.csv
@@ -1899,8 +1899,13 @@
        Usage: mlr sort-within-records [options]
        Outputs records sorted lexically ascending by keys.
        Options:
-       -r        Recursively sort subobjects/submaps, e.g. for JSON input.
-       -h|--help Show this message.
+       -f {names}   Sort only these keys; others preserve record order.
+       -r {regex}   Sort only keys matching this regex; others preserve record order.
+                    Example: -r '^[xy]' sorts keys starting with x or y.
+                    With no regex argument, -r recursively sorts subobjects/submaps
+                    (e.g. for JSON input), or combines with -f to treat names as regex.
+       -n           Sort field names naturally (e.g. 2 before 12). Combines with -f/-r.
+       -h|--help    Show this message.
 
    1msparsify0m
        Usage: mlr sparsify [options]
diff --git a/man/manpage.txt b/man/manpage.txt
index 72735e79a..ae5d678ff 100644
--- a/man/manpage.txt
+++ b/man/manpage.txt
@@ -27,7 +27,7 @@
        insertion-ordered hash map.  This encompasses a variety of data
        formats, including but not limited to the familiar CSV, TSV, and JSON.
        (Miller can handle positionally-indexed data as a special case.) This
-       manpage documents mlr 6.18.0.
+       manpage documents mlr 6.18.1.
 
 1mEXAMPLES0m
        mlr --icsv --opprint cat example.csv
@@ -1899,8 +1899,13 @@
        Usage: mlr sort-within-records [options]
        Outputs records sorted lexically ascending by keys.
        Options:
-       -r        Recursively sort subobjects/submaps, e.g. for JSON input.
-       -h|--help Show this message.
+       -f {names}   Sort only these keys; others preserve record order.
+       -r {regex}   Sort only keys matching this regex; others preserve record order.
+                    Example: -r '^[xy]' sorts keys starting with x or y.
+                    With no regex argument, -r recursively sorts subobjects/submaps
+                    (e.g. for JSON input), or combines with -f to treat names as regex.
+       -n           Sort field names naturally (e.g. 2 before 12). Combines with -f/-r.
+       -h|--help    Show this message.
 
    1msparsify0m
        Usage: mlr sparsify [options]
diff --git a/man/mlr.1 b/man/mlr.1
index b6e81d124..3f7dfc300 100644
--- a/man/mlr.1
+++ b/man/mlr.1
@@ -47,7 +47,7 @@ on integer-indexed fields: if the natural data structure for the latter is the
 array, then Miller's natural data structure is the insertion-ordered hash map.
 This encompasses a variety of data formats, including but not limited to the
 familiar CSV, TSV, and JSON.  (Miller can handle positionally-indexed data as
-a special case.) This manpage documents mlr 6.18.0.
+a special case.) This manpage documents mlr 6.18.1.
 .SH "EXAMPLES"
 .sp
 
@@ -2386,8 +2386,13 @@ which is the same as:
 Usage: mlr sort-within-records [options]
 Outputs records sorted lexically ascending by keys.
 Options:
--r        Recursively sort subobjects/submaps, e.g. for JSON input.
--h|--help Show this message.
+-f {names}   Sort only these keys; others preserve record order.
+-r {regex}   Sort only keys matching this regex; others preserve record order.
+             Example: -r '^[xy]' sorts keys starting with x or y.
+             With no regex argument, -r recursively sorts subobjects/submaps
+             (e.g. for JSON input), or combines with -f to treat names as regex.
+-n           Sort field names naturally (e.g. 2 before 12). Combines with -f/-r.
+-h|--help    Show this message.
 .fi
 .if n \{\
 .RE
diff --git a/miller.spec b/miller.spec
index 2b8684eb9..f2f070a60 100644
--- a/miller.spec
+++ b/miller.spec
@@ -1,6 +1,6 @@
 Summary: Name-indexed data processing tool
 Name: miller
-Version: 6.18.0
+Version: 6.18.1
 Release: 1%{?dist}
 License: BSD
 Source: https://github.com/johnkerl/miller/releases/download/%{version}/miller-%{version}.tar.gz
@@ -36,6 +36,9 @@ make install
 %{_mandir}/man1/mlr.1*
 
 %changelog
+* Sun Apr 19 2026 John Kerl <kerl.john.r@gmail.com> - 6.18.1-1
+- 6.18.1 release
+
 * Sun Apr 19 2026 John Kerl <kerl.john.r@gmail.com> - 6.18.0-1
 - 6.18.0 release
 
diff --git a/pkg/version/version.go b/pkg/version/version.go
index 43afd9e66..76828d4f5 100644
--- a/pkg/version/version.go
+++ b/pkg/version/version.go
@@ -4,4 +4,4 @@ package version
 // Nominally things like "6.0.0" for a release, then "6.0.0-dev" in between.
 // This makes it clear that a given build is on the main dev branch, not a
 // particular snapshot tag.
-var STRING string = "6.18.0-dev"
+var STRING string = "6.18.1"