diff --git a/internal/pkg/parsing/lexer/lexer.go b/internal/pkg/parsing/lexer/lexer.go
index db7735e43..e2ead0fc2 100644
--- a/internal/pkg/parsing/lexer/lexer.go
+++ b/internal/pkg/parsing/lexer/lexer.go
@@ -3,7 +3,7 @@
 package lexer
 
 import (
-	"os"
+	"io/ioutil"
 	"unicode/utf8"
 
 	"github.com/johnkerl/miller/internal/pkg/parsing/token"
@@ -45,7 +45,7 @@ func (s *SourceContext) Source() string {
 }
 
 func NewLexerFile(fpath string) (*Lexer, error) {
-	src, err := os.ReadFile(fpath)
+	src, err := ioutil.ReadFile(fpath)
 	if err != nil {
 		return nil, err
 	}
diff --git a/tools/build-dsl b/tools/build-dsl
index eacbffc68..c31f0ba52 100755
--- a/tools/build-dsl
+++ b/tools/build-dsl
@@ -52,4 +52,8 @@ fi
 # Override GOCC codegen with customized error handling
 cp internal/pkg/parsing/errors.go.template internal/pkg/parsing/errors/errors.go
 
+# We might need a manual replace of os.ReadFile by ioutil.ReadFile in autogen code.  Note we don't
+# use latest-and-greatest Go compiler version in our go.mod since we want to build on Centos which
+# can be trailing-edge in that regard.
+
 for x in internal/pkg/parsing/*/*.go; do gofmt -w $x; done