diff --git a/src/uu/uniq/Cargo.toml b/src/uu/uniq/Cargo.toml
index c1d3cb9ad..cd0fdad6f 100644
--- a/src/uu/uniq/Cargo.toml
+++ b/src/uu/uniq/Cargo.toml
@@ -15,7 +15,7 @@ edition = "2021"
 path = "src/uniq.rs"
 
 [dependencies]
-clap = { version = "3.2", features = ["wrap_help", "cargo"] }
+clap = { version = "4.0", features = ["wrap_help", "cargo"] }
 strum = "0.24.1"
 strum_macros = "0.24.2"
 uucore = { version=">=0.0.16", package="uucore", path="../../uucore" }
diff --git a/src/uu/uniq/src/uniq.rs b/src/uu/uniq/src/uniq.rs
index e2edae335..45f5c05f2 100644
--- a/src/uu/uniq/src/uniq.rs
+++ b/src/uu/uniq/src/uniq.rs
@@ -8,7 +8,7 @@
 // TODO remove this when https://github.com/rust-lang/rust-clippy/issues/6902 is fixed
 #![allow(clippy::use_self)]
 
-use clap::{crate_version, Arg, ArgMatches, Command};
+use clap::{crate_version, Arg, ArgAction, ArgMatches, Command};
 use std::fs::File;
 use std::io::{self, stdin, stdout, BufRead, BufReader, BufWriter, Read, Write};
 use std::path::Path;
@@ -255,10 +255,8 @@ fn get_long_usage() -> String {
 
 #[uucore::main]
 pub fn uumain(args: impl uucore::Args) -> UResult<()> {
-    let long_usage = get_long_usage();
-
     let matches = uu_app()
-        .after_help(&long_usage[..])
+        .after_help(get_long_usage())
         .try_get_matches_from(args)?;
 
     let files: Vec<String> = matches
@@ -276,18 +274,18 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
     };
 
     let uniq = Uniq {
-        repeats_only: matches.contains_id(options::REPEATED)
+        repeats_only: matches.get_flag(options::REPEATED)
             || matches.contains_id(options::ALL_REPEATED),
-        uniques_only: matches.contains_id(options::UNIQUE),
+        uniques_only: matches.get_flag(options::UNIQUE),
         all_repeated: matches.contains_id(options::ALL_REPEATED)
             || matches.contains_id(options::GROUP),
         delimiters: get_delimiter(&matches),
-        show_counts: matches.contains_id(options::COUNT),
+        show_counts: matches.get_flag(options::COUNT),
         skip_fields: opt_parsed(options::SKIP_FIELDS, &matches)?,
         slice_start: opt_parsed(options::SKIP_CHARS, &matches)?,
         slice_stop: opt_parsed(options::CHECK_CHARS, &matches)?,
-        ignore_case: matches.contains_id(options::IGNORE_CASE),
-        zero_terminated: matches.contains_id(options::ZERO_TERMINATED),
+        ignore_case: matches.get_flag(options::IGNORE_CASE),
+        zero_terminated: matches.get_flag(options::ZERO_TERMINATED),
     };
 
     if uniq.show_counts && uniq.all_repeated {
@@ -303,7 +301,7 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
     )
 }
 
-pub fn uu_app<'a>() -> Command<'a> {
+pub fn uu_app() -> Command {
     Command::new(uucore::util_name())
         .version(crate_version!())
         .about(ABOUT)
@@ -320,8 +318,7 @@ pub fn uu_app<'a>() -> Command<'a> {
                 ])
                 .help("print all duplicate lines. Delimiting is done with blank lines. [default: none]")
                 .value_name("delimit-method")
-                .min_values(0)
-                .max_values(1)
+                .num_args(0..=1)
                 .default_missing_value("none")
                 .require_equals(true),
         )
@@ -336,8 +333,7 @@ pub fn uu_app<'a>() -> Command<'a> {
                 ])
                 .help("show all items, separating groups with an empty line. [default: separate]")
                 .value_name("group-method")
-                .min_values(0)
-                .max_values(1)
+                .num_args(0..=1)
                 .default_missing_value("separate")
                 .require_equals(true)
                 .conflicts_with_all(&[
@@ -357,19 +353,22 @@ pub fn uu_app<'a>() -> Command<'a> {
             Arg::new(options::COUNT)
                 .short('c')
                 .long(options::COUNT)
-                .help("prefix lines by the number of occurrences"),
+                .help("prefix lines by the number of occurrences")
+                .action(ArgAction::SetTrue),
         )
         .arg(
             Arg::new(options::IGNORE_CASE)
                 .short('i')
                 .long(options::IGNORE_CASE)
-                .help("ignore differences in case when comparing"),
+                .help("ignore differences in case when comparing")
+                .action(ArgAction::SetTrue),
         )
         .arg(
             Arg::new(options::REPEATED)
                 .short('d')
                 .long(options::REPEATED)
-                .help("only print duplicate lines"),
+                .help("only print duplicate lines")
+                .action(ArgAction::SetTrue),
         )
         .arg(
             Arg::new(options::SKIP_CHARS)
@@ -389,19 +388,20 @@ pub fn uu_app<'a>() -> Command<'a> {
             Arg::new(options::UNIQUE)
                 .short('u')
                 .long(options::UNIQUE)
-                .help("only print unique lines"),
+                .help("only print unique lines")
+                .action(ArgAction::SetTrue),
         )
         .arg(
             Arg::new(options::ZERO_TERMINATED)
                 .short('z')
                 .long(options::ZERO_TERMINATED)
-                .help("end lines with 0 byte, not newline"),
+                .help("end lines with 0 byte, not newline")
+                .action(ArgAction::SetTrue),
         )
         .arg(
             Arg::new(ARG_FILES)
-                .multiple_occurrences(true)
-                .takes_value(true)
-                .max_values(2)
+                .action(ArgAction::Append)
+                .num_args(0..=2)
                 .value_hint(clap::ValueHint::FilePath),
         )
 }