diff --git a/manifest.json b/manifest.json
index f4da9df..80ea4ab 100644
--- a/manifest.json
+++ b/manifest.json
@@ -6,7 +6,7 @@
         "en": "Alternative front-end for Twitter that respects your privacy",
         "fr": "Interface alternative pour Twitter qui respecte votre vie privée"
     },
-    "version": "0.2021.02.16~ynh2",
+    "version": "0.2021.02.16~ynh4",
     "url": "https://github.com/zedeus/nitter",
     "license": "AGPL-3.0-only",
     "maintainer": {
diff --git a/scripts/_common.sh b/scripts/_common.sh
index 4936104..a2f9883 100644
--- a/scripts/_common.sh
+++ b/scripts/_common.sh
@@ -5,7 +5,7 @@
 #=================================================
 
 # dependencies used by the app
-pkg_dependencies="nim redis-server libsass-dev"
+pkg_dependencies="acl nim redis-server libsass-dev"
 
 #=================================================
 # PERSONAL HELPERS
diff --git a/scripts/backup b/scripts/backup
index 0b037b0..d72c557 100755
--- a/scripts/backup
+++ b/scripts/backup
@@ -15,7 +15,6 @@ source /usr/share/yunohost/helpers
 #=================================================
 
 ynh_clean_setup () {
-	### Remove this function if there's nothing to clean before calling the remove script.
 	true
 }
 # Exit if an error occurs during the execution of the script
@@ -36,11 +35,6 @@ domain=$(ynh_app_setting_get --app=$app --key=domain)
 #=================================================
 ynh_print_info --message="Declaring files to be backed up..."
 
-### N.B. : the following 'ynh_backup' calls are only a *declaration* of what needs
-### to be backuped and not an actual copy of any file. The actual backup that
-### creates and fill the archive with the files happens in the core after this
-### script is called. Hence ynh_backups calls takes basically 0 seconds to run.
-
 #=================================================
 # BACKUP THE APP MAIN DIR
 #=================================================
diff --git a/scripts/install b/scripts/install
index cc1de53..65f69dd 100755
--- a/scripts/install
+++ b/scripts/install
@@ -48,35 +48,15 @@ else
 fi
 hmac_key=$(ynh_string_random --length=64)
 
-### If it's a multi-instance app, meaning it can be installed several times independently
-### The id of the app as stated in the manifest is available as $YNH_APP_ID
-### The instance number is available as $YNH_APP_INSTANCE_NUMBER (equals "1", "2"...)
-### The app instance name is available as $YNH_APP_INSTANCE_NAME
-###    - the first time the app is installed, YNH_APP_INSTANCE_NAME = ynhexample
-###    - the second time the app is installed, YNH_APP_INSTANCE_NAME = ynhexample__2
-###    - ynhexample__{N} for the subsequent installations, with N=3,4...
-### The app instance name is probably what interests you most, since this is
-### guaranteed to be unique. This is a good unique identifier to define installation path,
-### db names...
 app=$YNH_APP_INSTANCE_NAME
 
 #=================================================
 # CHECK IF THE APP CAN BE INSTALLED WITH THESE ARGS
 #=================================================
-### About --weight and --time
-### ynh_script_progression will show to your final users the progression of each scripts.
-### In order to do that, --weight will represent the relative time of execution compared to the other steps in the script.
-### is a packager option, it will show you the execution time since the previous call.
-### This option should be removed before releasing your app.
-### Use the execution time, given by --time, to estimate the weight of a step.
-### A common way to do it is to set a weight equal to the execution time in second +1.
-### The execution time is given for the duration since the previous call. So the weight should be applied to this previous call.
 ynh_script_progression --message="Validating installation parameters..." --weight=1
 
 arch=$(ynh_detect_arch)
 
-### If the app uses NGINX as web server (written in HTML/PHP in most cases), the final path should be "/var/www/$app".
-### If the app provides an internal web server (or uses another application server such as uWSGI), the final path should be "/opt/yunohost/$app"
 final_path=/opt/yunohost/$app
 test ! -e "$final_path" || ynh_die --message="This path already contains a folder"
 
@@ -107,11 +87,6 @@ ynh_app_setting_set --app=$app --key=hmac_key --value=$hmac_key
 #=================================================
 ynh_script_progression --message="Finding an available port..." --weight=1
 
-### Use these lines if you have to open a port for the application
-### `ynh_find_port` will find the first available port starting from the given port.
-### If you're not using these lines:
-###		- Remove the section "CLOSE A PORT" in the remove script
-
 # Find an available port
 port=$(ynh_find_port --port=8080)
 ynh_app_setting_set --app=$app --key=port --value=$port
@@ -121,14 +96,6 @@ ynh_app_setting_set --app=$app --key=port --value=$port
 #=================================================
 ynh_script_progression --message="Installing dependencies..." --weight=1
 
-### `ynh_install_app_dependencies` allows you to add any "apt" dependencies to the package.
-### Those deb packages will be installed as dependencies of this package.
-### If you're not using this helper:
-###		- Remove the section "REMOVE DEPENDENCIES" in the remove script
-###		- Remove the variable "pkg_dependencies" in _common.sh
-###		- As well as the section "REINSTALL DEPENDENCIES" in the restore script
-###		- And the section "UPGRADE DEPENDENCIES" in the upgrade script
-
 ynh_install_app_dependencies $pkg_dependencies
 
 #=================================================
@@ -136,10 +103,6 @@ ynh_install_app_dependencies $pkg_dependencies
 #=================================================
 ynh_script_progression --message="Setting up source files..." --weight=1
 
-### `ynh_setup_source` is used to install an app from a zip or tar.gz file,
-### downloaded from an upstream source, like a git repository.
-### `ynh_setup_source` use the file conf/app.src
-
 ynh_app_setting_set --app=$app --key=final_path --value=$final_path
 # Download, check integrity, uncompress and patch the source from app.src
 ynh_setup_source --dest_dir="$final_path"
@@ -151,8 +114,6 @@ ynh_setup_source --source_id="nim_$arch" --dest_dir="$final_path/.nim" || ynh_di
 #=================================================
 ynh_script_progression --message="Configuring NGINX web server..." --weight=1
 
-### `ynh_add_nginx_config` will use the file conf/nginx.conf
-
 # Create a dedicated NGINX config
 ynh_add_nginx_config
 
@@ -182,106 +143,39 @@ popd || ynh_die
 #=================================================
 ynh_script_progression --message="Configuring a systemd service..." --weight=1
 
-### `ynh_systemd_config` is used to configure a systemd script for an app.
-### It can be used for apps that use sysvinit (with adaptation) or systemd.
-### Have a look at the app to be sure this app needs a systemd script.
-### `ynh_systemd_config` will use the file conf/systemd.service
-### If you're not using these lines:
-###		- You can remove those files in conf/.
-###		- Remove the section "BACKUP SYSTEMD" in the backup script
-###		- Remove also the section "STOP AND REMOVE SERVICE" in the remove script
-###		- As well as the section "RESTORE SYSTEMD" in the restore script
-###		- And the section "SETUP SYSTEMD" in the upgrade script
-
 # Create a dedicated systemd config
 ynh_add_systemd_config
 
 #=================================================
 # ADD A CONFIGURATION
 #=================================================
-
-### You can add specific configuration files.
-###
-### Typically, put your template conf file in ../conf/your_config_file
-### The template may contain strings such as __FOO__ or __FOO_BAR__,
-### which will automatically be replaced by the values of $foo and $foo_bar
-###
-### ynh_add_config will also keep track of the config file's checksum,
-### which later during upgrade may allow to automatically backup the config file
-### if it's found that the file was manually modified
-###
-### Check the documentation of `ynh_add_config` for more info.
-
 ynh_add_config --template="nitter.conf" --destination="$final_path/nitter.conf"
 
-### For more complex cases where you want to replace stuff using regexes,
-### you shoud rely on ynh_replace_string (which is basically a wrapper for sed)
-### When doing so, you also need to manually call ynh_store_file_checksum
-###
-### ynh_replace_string --match_string="match_string" --replace_string="replace_string" --target_file="$final_path/some_config_file"
-### ynh_store_file_checksum --file="$final_path/some_config_file"
-
 #=================================================
 # GENERIC FINALIZATION
 #=================================================
 # SECURE FILES AND DIRECTORIES
 #=================================================
-
-### For security reason, any app should set the permissions to root: before anything else.
-### Then, if write authorization is needed, any access should be given only to directories
-### that really need such authorization.
-
 # Set permissions to app files
 chown -R root:$app $final_path
 chown -R $app:$app $final_path/tmp
 chmod -R o-rwx $final_path
 chmod -R g-w $final_path
+setfacl -n -m user:www-data:rx $final_path
+setfacl -n -R -m user:www-data:rx -m default:user:www-data:rx $final_path/public
 
 #=================================================
 # INTEGRATE SERVICE IN YUNOHOST
 #=================================================
 ynh_script_progression --message="Integrating service in YunoHost..." --weight=1
 
-### `yunohost service add` integrates a service in YunoHost. It then gets
-### displayed in the admin interface and through the others `yunohost service` commands.
-### (N.B.: this line only makes sense if the app adds a service to the system!)
-### If you're not using these lines:
-###		- You can remove these files in conf/.
-###		- Remove the section "REMOVE SERVICE INTEGRATION IN YUNOHOST" in the remove script
-###		- As well as the section "INTEGRATE SERVICE IN YUNOHOST" in the restore script
-###		- And the section "INTEGRATE SERVICE IN YUNOHOST" in the upgrade script
-
 yunohost service add $app --description="Alternative front-end for Twitter that respects your privacy" --log="/var/log/$app/$app.log"
 
-### Additional options starting with 3.8:
-###
-### --needs_exposed_ports "$port" a list of ports that needs to be publicly exposed
-###                               which will then be checked by YunoHost's diagnosis system
-###                               (N.B. DO NOT USE THIS is the port is only internal!!!)
-###
-### --test_status "some command"  a custom command to check the status of the service
-###                               (only relevant if 'systemctl status' doesn't do a good job)
-###
-### --test_conf "some command"    some command similar to "nginx -t" that validates the conf of the service
-###
-### Re-calling 'yunohost service add' during the upgrade script is the right way
-### to proceed if you later realize that you need to enable some flags that
-### weren't enabled on old installs (be careful it'll override the existing
-### service though so you should re-provide all relevant flags when doing so)
-
 #=================================================
 # START SYSTEMD SERVICE
 #=================================================
 ynh_script_progression --message="Starting a systemd service..." --weight=1
 
-### `ynh_systemd_action` is used to start a systemd service for an app.
-### Only needed if you have configure a systemd service
-### If you're not using these lines:
-###		- Remove the section "STOP SYSTEMD SERVICE" and "START SYSTEMD SERVICE" in the backup script
-###		- As well as the section "START SYSTEMD SERVICE" in the restore script
-###		- As well as the section"STOP SYSTEMD SERVICE" and "START SYSTEMD SERVICE" in the upgrade script
-###		- And the section "STOP SYSTEMD SERVICE" and "START SYSTEMD SERVICE" in the change_url script
-
 # Start a systemd service
 ynh_systemd_action --service_name=$app --action="start" --log_path="/var/log/$app/$app.log"
 
diff --git a/scripts/restore b/scripts/restore
index 6a6fe13..e6f8b5c 100755
--- a/scripts/restore
+++ b/scripts/restore
@@ -15,7 +15,6 @@ source /usr/share/yunohost/helpers
 #=================================================
 
 ynh_clean_setup () {
-	#### Remove this function if there's nothing to clean before calling the remove script.
 	true
 }
 # Exit if an error occurs during the execution of the script
@@ -65,14 +64,6 @@ ynh_script_progression --message="Recreating the dedicated system user..." --wei
 # Create the dedicated user (if not existing)
 ynh_system_user_create --username=$app
 
-#=================================================
-# REINSTALL DEPENDENCIES
-#=================================================
-ynh_script_progression --message="Reinstalling dependencies..." --weight=1
-
-# Define and install dependencies
-ynh_install_app_dependencies $pkg_dependencies
-
 #=================================================
 # RESTORE USER RIGHTS
 #=================================================
@@ -82,6 +73,16 @@ chown -R root:$app $final_path
 chown -R $app:$app $final_path/tmp
 chmod -R o-rwx $final_path
 chmod -R g-w $final_path
+setfacl -n -m user:www-data:rx $final_path
+setfacl -n -R -m user:www-data:rx -m default:user:www-data:rx $final_path/public
+
+#=================================================
+# REINSTALL DEPENDENCIES
+#=================================================
+ynh_script_progression --message="Reinstalling dependencies..." --weight=1
+
+# Define and install dependencies
+ynh_install_app_dependencies $pkg_dependencies
 
 #=================================================
 # SPECIFIC RESTORATION
diff --git a/scripts/upgrade b/scripts/upgrade
index effc991..3a15ad0 100644
--- a/scripts/upgrade
+++ b/scripts/upgrade
@@ -34,12 +34,6 @@ hmac_key=$(ynh_app_setting_get --app=$app --key=hmac_key)
 # CHECK VERSION
 #=================================================
 
-### This helper will compare the version of the currently installed app and the version of the upstream package.
-### $upgrade_type can have 2 different values
-### - UPGRADE_APP if the upstream app version has changed
-### - UPGRADE_PACKAGE if only the YunoHost package has changed
-### ynh_check_app_version_changed will stop the upgrade if the app is up to date.
-### UPGRADE_APP should be used to upgrade the core app only if there's an upgrade to do.
 upgrade_type=$(ynh_check_app_version_changed)
 
 #=================================================
@@ -129,21 +123,8 @@ ynh_add_systemd_config
 #=================================================
 # UPDATE A CONFIG FILE
 #=================================================
-
-### Same as during install
-###
-### The file will automatically be backed-up if it's found to be manually modified (because
-### ynh_add_config keeps track of the file's checksum)
-
 ynh_add_config --template="nitter.conf" --destination="$final_path/nitter.conf"
 
-### For more complex cases where you want to replace stuff using regexes,
-### you shoud rely on ynh_replace_string (which is basically a wrapper for sed)
-### When doing so, you also need to manually call ynh_store_file_checksum
-###
-### ynh_replace_string --match_string="match_string" --replace_string="replace_string" --target_file="$final_path/some_config_file"
-### ynh_store_file_checksum --file="$final_path/some_config_file"
-
 #=================================================
 # GENERIC FINALIZATION
 #=================================================
@@ -155,6 +136,8 @@ chown -R root:$app $final_path
 chown -R $app:$app $final_path/tmp
 chmod -R o-rwx $final_path
 chmod -R g-w $final_path
+setfacl -n -m user:www-data:rx $final_path
+setfacl -n -R -m user:www-data:rx -m default:user:www-data:rx $final_path/public
 
 #=================================================
 # INTEGRATE SERVICE IN YUNOHOST