diff --git a/.github/workflows/pr-lint.yml b/.github/workflows/pr-lint.yml
index 59e176a5e0..704c614549 100644
--- a/.github/workflows/pr-lint.yml
+++ b/.github/workflows/pr-lint.yml
@@ -22,6 +22,7 @@ jobs:
           types: |
             feat
             fix
+            improvement
             chore
             docs
             deps
@@ -38,9 +39,9 @@ jobs:
           TITLE: ${{ github.event.pull_request.title }}
         run: |
           title_length=${#TITLE}
-          if [ $title_length -gt 72 ]
+          if [ $title_length -gt 85 ]
           then
-            echo "PR title is too long (greater than 72 characters)"
+            echo "PR title is too long (greater than 85 characters)"
             exit 1
           fi
 
diff --git a/mm2src/common/common.rs b/mm2src/common/common.rs
index e0b6b4d233..288882d0ae 100644
--- a/mm2src/common/common.rs
+++ b/mm2src/common/common.rs
@@ -162,14 +162,14 @@ use std::convert::TryInto;
 use std::fmt::Write as FmtWrite;
 use std::fs::File;
 use std::future::Future as Future03;
-use std::io::{BufReader, Read, Write};
+use std::io::{self, BufReader, Read, Write};
 use std::iter::Peekable;
 use std::mem::{forget, zeroed};
 use std::num::{NonZeroUsize, TryFromIntError};
 use std::ops::{Add, Deref, Div, RangeInclusive};
 use std::os::raw::c_void;
 use std::panic::{set_hook, PanicInfo};
-use std::path::PathBuf;
+use std::path::{Path, PathBuf};
 use std::ptr::read_volatile;
 use std::sync::atomic::Ordering;
 use std::time::{Duration, SystemTime, SystemTimeError};
@@ -792,7 +792,7 @@ pub fn kdf_app_dir() -> Option<PathBuf> {
 }
 
 /// Returns path of the coins file.
-pub fn kdf_coins_file() -> PathBuf {
+pub fn kdf_coins_file() -> Result<PathBuf, io::Error> {
     #[cfg(not(target_arch = "wasm32"))]
     let value_from_env = env::var("MM_COINS_PATH").ok();
 
@@ -803,7 +803,7 @@ pub fn kdf_coins_file() -> PathBuf {
 }
 
 /// Returns path of the config file.
-pub fn kdf_config_file() -> PathBuf {
+pub fn kdf_config_file() -> Result<PathBuf, io::Error> {
     #[cfg(not(target_arch = "wasm32"))]
     let value_from_env = env::var("MM_CONF_PATH").ok();
 
@@ -819,16 +819,41 @@ pub fn kdf_config_file() -> PathBuf {
 ///  1- From the environment variable.
 ///  2- From the current directory where app is called.
 ///  3- From the root application directory.
-pub fn find_kdf_dependency_file(value_from_env: Option<String>, path_leaf: &str) -> PathBuf {
+fn find_kdf_dependency_file(value_from_env: Option<String>, path_leaf: &str) -> Result<PathBuf, io::Error> {
     if let Some(path) = value_from_env {
-        return PathBuf::from(path);
+        let path = PathBuf::from(path);
+        require_file(&path)?;
+        return Ok(path);
     }
 
     let from_current_dir = PathBuf::from(path_leaf);
-    if from_current_dir.exists() {
+
+    let path = if from_current_dir.exists() {
         from_current_dir
     } else {
         kdf_app_dir().unwrap_or_default().join(path_leaf)
+    };
+
+    require_file(&path)?;
+    return Ok(path);
+
+    fn require_file(path: &Path) -> Result<(), io::Error> {
+        if path.is_dir() {
+            // TODO: use `IsADirectory` variant which is stabilized with 1.83
+            return Err(io::Error::new(
+                io::ErrorKind::InvalidInput,
+                format!("Expected file but '{}' is a directory.", path.display()),
+            ));
+        }
+
+        if !path.exists() {
+            return Err(io::Error::new(
+                io::ErrorKind::NotFound,
+                format!("File '{}' is not present.", path.display()),
+            ));
+        }
+
+        Ok(())
     }
 }
 
diff --git a/mm2src/mm2_main/src/mm2.rs b/mm2src/mm2_main/src/mm2.rs
index dd7c7bed27..600702b921 100644
--- a/mm2src/mm2_main/src/mm2.rs
+++ b/mm2src/mm2_main/src/mm2.rs
@@ -303,22 +303,23 @@ pub fn mm2_main(version: String, datetime: String) {
 /// Parses and returns the `first_arg` as JSON.
 /// Attempts to load the config from `MM2.json` file if `first_arg` is None
 pub fn get_mm2config(first_arg: Option<&str>) -> Result<Json, String> {
-    let conf_path = common::kdf_config_file();
-    let conf_from_file = slurp(&conf_path);
     let conf = match first_arg {
-        Some(s) => s,
+        Some(s) => s.to_owned(),
         None => {
+            let conf_path = common::kdf_config_file().map_err(|e| e.to_string())?;
+            let conf_from_file = slurp(&conf_path);
+
             if conf_from_file.is_empty() {
                 return ERR!(
                     "Config is not set from command line arg and {} file doesn't exist.",
                     conf_path.display()
                 );
             }
-            try_s!(std::str::from_utf8(&conf_from_file))
+            try_s!(String::from_utf8(conf_from_file))
         },
     };
 
-    let mut conf: Json = match json::from_str(conf) {
+    let mut conf: Json = match json::from_str(&conf) {
         Ok(json) => json,
         // Syntax or io errors may include the conf string in the error message so we don't want to take risks and show these errors internals in the log.
         // If new variants are added to the Error enum, there can be a risk of exposing the conf string in the error message when updating serde_json so
@@ -327,7 +328,7 @@ pub fn get_mm2config(first_arg: Option<&str>) -> Result<Json, String> {
     };
 
     if conf["coins"].is_null() {
-        let coins_path = common::kdf_coins_file();
+        let coins_path = common::kdf_coins_file().map_err(|e| e.to_string())?;
 
         let coins_from_file = slurp(&coins_path);
         if coins_from_file.is_empty() {