diff --git a/README.md b/README.md
index ea9d9ba0..d9c50f7f 100644
--- a/README.md
+++ b/README.md
@@ -40,16 +40,12 @@ Calibre-Web is a web app providing a clean interface for browsing, reading and d
 ## Installation
 
 #### Installation via pip (recommended)
-1. Install calibre web via pip with the command `pip install calibreweb` (Depending on your OS and or distro the command could also be `pip3`). 
-2. Optional features can also be installed via pip, please refer to [this page](https://github.com/janeczku/calibre-web/wiki/Dependencies-in-Calibre-Web-Linux-Windows) for details 
-3. Calibre-Web can be started afterwards by typing `cps` or `python3 -m cps` 
+1. To avoid problems with already installed python dependencies, it's recommended to create a virtual environment for Calibre-Web
+2. Install Calibre-Web via pip with the command `pip install calibreweb` (Depending on your OS and or distro the command could also be `pip3`). 
+3. Optional features can also be installed via pip, please refer to [this page](https://github.com/janeczku/calibre-web/wiki/Dependencies-in-Calibre-Web-Linux-Windows) for details 
+4. Calibre-Web can be started afterwards by typing `cps` or `python3 -m cps` 
 
-#### Manual installation
-1. Install dependencies by running `pip3 install --target vendor -r requirements.txt` (python3.x). Alternativly set up a python virtual environment.
-2. Execute the command: `python3 cps.py` (or `nohup python3 cps.py` - recommended if you want to exit the terminal window)
-
-Issues with Ubuntu:
-Please note that running the above install command can fail on some versions of Ubuntu, saying `"can't combine user with prefix"`. This is a [known bug](https://github.com/pypa/pip/issues/3826) and can be remedied by using the command `pip install --system --target vendor -r requirements.txt` instead.
+In the Wiki there are also examples for a [manual installation](https://github.com/janeczku/calibre-web/wiki/Manual-installation) and for installation on [Linux Mint](https://github.com/janeczku/calibre-web/wiki/How-To:Install-Calibre-Web-in-Linux-Mint-19-or-20)
 
 ## Quick start
 
diff --git a/cps/converter.py b/cps/converter.py
index fcbabbfc..bb197467 100644
--- a/cps/converter.py
+++ b/cps/converter.py
@@ -27,7 +27,6 @@ from .subproc_wrapper import process_wait
 log = logger.create()
 
 # _() necessary to make babel aware of string for translation
-_NOT_CONFIGURED = _('not configured')
 _NOT_INSTALLED = _('not installed')
 _EXECUTION_ERROR = _('Execution permissions missing')
 
@@ -48,14 +47,16 @@ def _get_command_version(path, pattern, argument=None):
 
 
 def get_calibre_version():
-    return _get_command_version(config.config_converterpath, r'ebook-convert.*\(calibre', '--version') \
-           or _NOT_CONFIGURED
+    return _get_command_version(config.config_converterpath, r'ebook-convert.*\(calibre', '--version')
 
 
 def get_unrar_version():
-    return _get_command_version(config.config_rarfile_location, r'UNRAR.*\d') or _NOT_CONFIGURED
+    unrar_version = _get_command_version(config.config_rarfile_location, r'UNRAR.*\d')
+    if unrar_version == "not installed":
+        unrar_version = _get_command_version(config.config_rarfile_location, r'unrar.*\d','-V')
+    return unrar_version
 
 def get_kepubify_version():
-    return _get_command_version(config.config_kepubifypath, r'kepubify\s','--version') or _NOT_CONFIGURED
+    return _get_command_version(config.config_kepubifypath, r'kepubify\s','--version')
 
 
diff --git a/cps/updater.py b/cps/updater.py
index 2166b334..181c4374 100644
--- a/cps/updater.py
+++ b/cps/updater.py
@@ -214,7 +214,7 @@ class Updater(threading.Thread):
             if not os.path.exists(dst_dir):
                 try:
                     os.makedirs(dst_dir)
-                    log.debug('Create directory: {}', dst_dir)
+                    log.debug('Create directory: {}'.format(dst_dir))
                 except OSError as e:
                     log.error('Failed creating folder: {} with error {}'.format(dst_dir, e))
                 if change_permissions:
@@ -233,7 +233,7 @@ class Updater(threading.Thread):
                         permission = os.stat(dst_file)
                     try:
                         os.remove(dst_file)
-                        log.debug('Remove file before copy: %s', dst_file)
+                        log.debug('Remove file before copy: {}'.format(dst_file))
                     except OSError as e:
                         log.error('Failed removing file: {} with error {}'.format(dst_file, e))
                 else: