diff --git a/Cargo.toml b/Cargo.toml
index 4e5b4b3..9f2caeb 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -122,7 +122,7 @@ cleanhive = ["nt_hive2"]
 anyhow = "1.0"
 binread = "2.2.0"
 chrono = "0.4"
-clap = {version = "4", features = ["derive", "wrap_help", "cargo"] }
+clap = {version = "4.5", features = ["derive", "wrap_help", "cargo"] }
 clap-verbosity-flag = "2.0.0"
 csv = "1.2.2"
 encoding_rs = "0.8"
diff --git a/src/bin/mactime2/application.rs b/src/bin/mactime2/application.rs
index 8fb6cb2..e925a21 100644
--- a/src/bin/mactime2/application.rs
+++ b/src/bin/mactime2/application.rs
@@ -50,6 +50,7 @@ pub struct Mactime2Application {
     format: OutputFormat,
     bodyfile: Input,
     dst_zone: Tz,
+    show_headers: bool,
     strict_mode: bool,
 }
 
@@ -73,7 +74,11 @@ impl Mactime2Application {
                     Box::new(OldCsvOutput::new(std::io::stdout(), self.dst_zone))
                 }
 
-                OutputFormat::Csv => Box::new(CsvOutput::new(std::io::stdout(), self.dst_zone)),
+                OutputFormat::Csv => Box::new(CsvOutput::new(
+                    std::io::stdout(),
+                    self.dst_zone,
+                    self.show_headers,
+                )),
                 OutputFormat::Txt => Box::new(TxtOutput::new(std::io::stdout(), self.dst_zone)),
                 _ => panic!("invalid execution path"),
             });
@@ -117,6 +122,7 @@ impl From<Cli> for Mactime2Application {
             format,
             bodyfile: cli.input_file,
             dst_zone: cli.dst_zone.into_tz().unwrap(),
+            show_headers: cli.show_headers,
             strict_mode: cli.strict_mode,
         }
     }
diff --git a/src/bin/mactime2/cli.rs b/src/bin/mactime2/cli.rs
index faab3df..3ae6ea0 100644
--- a/src/bin/mactime2/cli.rs
+++ b/src/bin/mactime2/cli.rs
@@ -1,9 +1,9 @@
+use chrono_tz::Tz;
 use clap::{Parser, ValueHint};
 use clio::Input;
 use log::LevelFilter;
-use chrono_tz::Tz;
 
-use dfir_toolkit::common::{HasVerboseFlag,TzArgument};
+use dfir_toolkit::common::{HasVerboseFlag, TzArgument};
 
 use super::OutputFormat;
 
@@ -13,11 +13,13 @@ const BODYFILE_HELP: &str =
 #[cfg(not(feature = "gzip"))]
 const BODYFILE_HELP: &str = "path to input file or '-' for stdin";
 
-const AFTER_HELP: &str = color_print::cstr!(r##"<red><bold>IMPORTANT</bold>
+const AFTER_HELP: &str = color_print::cstr!(
+    r##"<red><bold>IMPORTANT</bold>
 
 Note that POSIX specifies that all UNIX timestamps are UTC timestamps. It is
 up to you to ensure that the bodyfile only contains UNIX timestamps that
-comply with the POSIX standard.</red>"##);
+comply with the POSIX standard.</red>"##
+);
 
 /// Replacement for `mactime`
 #[derive(Parser)]
@@ -29,22 +31,40 @@ pub struct Cli {
 
     /// output format, if not specified, default value is 'txt'
     #[clap(
+        id("format"),
         short('F'),
         long("format"),
         value_enum,
-        display_order(600)
-    )]
+        conflicts_with_all(["json", "csv"]),
+        display_order(600))]
     pub(crate) output_format: Option<OutputFormat>,
 
     /// output as CSV instead of TXT. This is a convenience option, which is identical to `--format=csv`
-    /// and will be removed in a future release. If you specified `--format` and `-d`, the latter will be ignored.
-    #[clap(short('d'), display_order(610))]
-    #[arg(group="csv")]
+    /// and will be removed in a future release.
+    #[clap(
+        id("csv"),
+        short('d'),
+        display_order(610),
+        conflicts_with_all(["json", "format"]))]
     pub(crate) csv_format: bool,
 
+    /// display a header line in the CSV output
+    #[clap(
+        id("show-headers"),
+        short('H'),
+        long("show-headers"),
+        display_order(615),
+        conflicts_with("json")
+    )]
+    pub(crate) show_headers: bool,
+
     /// output as JSON instead of TXT. This is a convenience option, which is identical to `--format=json`
-    /// and will be removed in a future release. If you specified `--format` and `-j`, the latter will be ignored.
-    #[clap(short('j'), display_order(620))]
+    /// and will be removed in a future release.
+    #[clap(
+        id("json"),
+        short('j'),
+        display_order(620),
+        conflicts_with_all(["csv", "format", "show-headers"]))]
     pub(crate) json_format: bool,
 
     /// name of offset of destination timezone (or 'list' to display all possible values
diff --git a/src/bin/mactime2/output/csv_output.rs b/src/bin/mactime2/output/csv_output.rs
index 7323c31..f7ed6fc 100644
--- a/src/bin/mactime2/output/csv_output.rs
+++ b/src/bin/mactime2/output/csv_output.rs
@@ -21,12 +21,12 @@ impl<W> CsvOutput<W>
 where
     W: Write + Send,
 {
-    pub fn new(writer: W, dst_zone: Tz) -> Self {
+    pub fn new(writer: W, dst_zone: Tz, has_headers: bool) -> Self {
         Self {
             dst_zone,
             writer: WriterBuilder::new()
                 .delimiter(CSV_DELIMITER)
-                .has_headers(false)
+                .has_headers(has_headers)
                 .from_writer(writer),
         }
     }
@@ -108,7 +108,7 @@ mod tests {
                 line: Arc::new(bf_line),
             };
 
-            let mut output = CsvOutput::new(Cursor::new(vec![]), Tz::UTC);
+            let mut output = CsvOutput::new(Cursor::new(vec![]), Tz::UTC, false);
             output.write_line(&unix_ts, &entry).unwrap();
             let mut output = BufReader::new(Cursor::new(output.into_writer().into_inner())).lines();
             let out_line = output.next().unwrap().unwrap();
@@ -136,7 +136,7 @@ mod tests {
                 line: Arc::new(bf_line),
             };
 
-            let mut output = CsvOutput::new(Cursor::new(vec![]), tz);
+            let mut output = CsvOutput::new(Cursor::new(vec![]), tz, false);
             let delimiter: char = crate::output::CSV_DELIMITER.into();
             output.write_line(&unix_ts, &entry).unwrap();
             let mut output = BufReader::new(Cursor::new(output.into_writer().into_inner())).lines();