diff --git a/conf/app.src b/conf/app.src
index e053788..a8392f7 100644
--- a/conf/app.src
+++ b/conf/app.src
@@ -1,5 +1,5 @@
-SOURCE_URL=https://github.com/standardnotes/syncing-server/archive/3.13.6.zip
-SOURCE_SUM=9b68e74e34dba5949f740ef6ce3b88b9eee43e29a8eac8aa2d1b3987263eff72
+SOURCE_URL=https://github.com/standardnotes/syncing-server/archive/3.20.4.zip
+SOURCE_SUM=A9FEBE8D31200580D2AEC3DF407F177F7A334C837386E7DD436F1754746A4EAA
 SOURCE_SUM_PRG=sha256sum
 SOURCE_FORMAT=zip
 SOURCE_IN_SUBDIR=true
diff --git a/conf/env.sample b/conf/env.sample
index d6a7f95..b6e20e6 100644
--- a/conf/env.sample
+++ b/conf/env.sample
@@ -11,7 +11,8 @@ EXPOSED_PORT=3000
 # change this to "production" for production use, otherwise the access token time is very short and forces re-login
 RAILS_ENV=development
 RAILS_LOG_TO_STDOUT=false
-RAILS_LOG_LEVEL=info # "debug" | "info" | "warn" | "error" | "fatal"
+# Log Level options: "INFO" | "DEBUG" | "INFO" | "WARN" | "ERROR" | "FATAL"
+RAILS_LOG_LEVEL=INFO
 #SQS_QUEUE=somequeue
 #SQS_QUEUE_LOW_PRIORITY=low_priority_queue
 #AWS_REGION=us-west1
@@ -63,6 +64,18 @@ EMAIL_ATTACHMENT_MAX_SIZE=10485760
 # Revisions persistency
 REVISIONS_FREQUENCY=300
 
+# (Optional) Redis Cache for ephemeral sessions
+REDIS_URL=redis://cache:6379
+
+# (Optional) Change URLs to Internal DNS
+#INTERNAL_DNS_REROUTE_ENABLED=false
+
+# (Optional) Auth Proxy JWT Secret
+#AUTH_JWT_SECRET=changeme123
+
+# (Optional) User Management Server - registration emails, subscriptions etc.
+#USER_MANAGEMENT_SERVER=
+
 # Sub-URI
 RAILS_RELATIVE_URL_ROOT=/
 
diff --git a/conf/systemd.service b/conf/systemd.service
index 145c806..58e06c1 100644
--- a/conf/systemd.service
+++ b/conf/systemd.service
@@ -1,6 +1,8 @@
 [Unit]
 Description=__APP__ service
 After=network.target
+After=mysql.service
+After=redis.service
 
 [Service]
 Type=simple
diff --git a/manifest.json b/manifest.json
index c7d9e3c..0018824 100644
--- a/manifest.json
+++ b/manifest.json
@@ -5,7 +5,7 @@
     "description": {
         "en": "The Standard Notes syncing server. An end-to-end encrypted note-taking app."
     },
-    "version": "3.13.6~ynh4",
+    "version": "3.20.4~ynh1",
     "url": "https://github.com/standardnotes/syncing-server",
     "license": "AGPL-3.0-or-later",
     "maintainer": {
diff --git a/scripts/install b/scripts/install
index 55325b4..63ac027 100755
--- a/scripts/install
+++ b/scripts/install
@@ -8,6 +8,7 @@
 
 source _common.sh
 source ynh_install_ruby
+source ynh_redis
 source /usr/share/yunohost/helpers
 
 #=================================================
@@ -54,6 +55,8 @@ ynh_app_setting_set --app=$app --key=path --value=$path_url
 ynh_app_setting_set --app=$app --key=is_public --value=$is_public
 ynh_app_setting_set --app=$app --key=access_domain --value=$access_domain
 ynh_app_setting_set --app=$app --key=mail --value=$mail
+redis_db=$(ynh_redis_get_free_db)
+ynh_app_setting_set --app=$app --key=redis_db --value="$redis_db"
 
 #=================================================
 # STANDARD MODIFICATIONS
@@ -148,6 +151,7 @@ ynh_replace_string --match_string="SMTP_PORT=.*$" --replace_string="SMTP_PORT=25
 ynh_replace_string --match_string="SMTP_DOMAIN=.*$" --replace_string="SMTP_DOMAIN=localhost" --target_file="$config_file"
 ynh_replace_string --match_string="SMTP_STARTTLS=.*$" --replace_string="SMTP_STARTTLS=" --target_file="$config_file"
 ynh_replace_string --match_string="RAILS_SERVE_STATIC_FILES=.*$" --replace_string="RAILS_SERVE_STATIC_FILES=true" --target_file="$config_file"
+ynh_replace_string --match_string="REDIS_URL.*$" --replace_string="REDIS_URL=redis://localhost:6379/$redis_db" --target_file="$config_file"
 
 ynh_replace_string --match_string="__MAIL__" --replace_string="$mail" --target_file="$final_path/live/app/mailers/application_mailer.rb"
 ynh_replace_string --match_string="__DOMAIN__" --replace_string="$domain" --target_file="$final_path/live/app/views/user_mailer/welcome.html.erb"
@@ -164,7 +168,8 @@ pushd "$final_path/live"
     exec_as "$app" env PATH=$PATH /opt/rbenv/versions/$RUBY_VERSION/bin/bundle config set path 'vendor/bundle'
     exec_as "$app" env PATH=$PATH /opt/rbenv/versions/$RUBY_VERSION/bin/bundle config set with 'development'
     exec_as "$app" env PATH=$PATH /opt/rbenv/versions/$RUBY_VERSION/bin/bundle install
-    exec_as "$app" env PATH=$PATH RAILS_ENV=production /opt/rbenv/versions/$RUBY_VERSION/bin/bundle exec rails db:create db:migrate --quiet
+    exec_as "$app" env PATH=$PATH RAILS_ENV=production /opt/rbenv/versions/$RUBY_VERSION/bin/bundle exec rails db:migrate --quiet
+    exec_as "$app" env PATH=$PATH RAILS_ENV=production /opt/rbenv/versions/$RUBY_VERSION/bin/bundle exec rails db:seed --quiet
 #    exec_as "$app" env PATH=$PATH RAILS_ENV=production /opt/rbenv/versions/$RUBY_VERSION/bin/bundle exec rails assets:precompile --quiet
 popd
 
diff --git a/scripts/remove b/scripts/remove
index 99575ef..90dcfbe 100755
--- a/scripts/remove
+++ b/scripts/remove
@@ -8,6 +8,7 @@
 
 source _common.sh
 source ynh_install_ruby
+source ynh_redis
 source /usr/share/yunohost/helpers
 
 #=================================================
@@ -52,6 +53,13 @@ ynh_script_progression --message="Removing the MySQL database..."  --weight=1
 # Remove a database if it exists, along with the associated user
 ynh_mysql_remove_db --db_user=$db_user --db_name=$db_name
 
+##=================================================
+## REMOVE REDIS DB
+##=================================================
+ynh_script_progression --message="Removing the Redis database..."  --weight=1
+
+ynh_redis_remove_db
+
 #=================================================
 # REMOVE DEPENDENCIES
 #=================================================
diff --git a/scripts/restore b/scripts/restore
index 2f5ab51..5e401db 100755
--- a/scripts/restore
+++ b/scripts/restore
@@ -9,6 +9,7 @@
 #Keep this path for calling _common.sh inside the execution's context of backup and restore scripts
 source ../settings/scripts/_common.sh
 source ../settings/scripts/ynh_install_ruby
+source ../settings/scripts/ynh_redis
 source /usr/share/yunohost/helpers
 
 #=================================================
@@ -36,6 +37,11 @@ db_name=$(ynh_app_setting_get --app=$app --key=db_name)
 db_user=$db_name
 db_pwd=$(ynh_app_setting_get --app=$app --key=mysqlpwd)
 
+redis_db=$(ynh_redis_get_free_db)
+ynh_app_setting_set --app=$app --key=redis_db --value="$redis_db"
+
+config_file="$final_path/live/.env"
+
 #=================================================
 # CHECK IF THE APP CAN BE RESTORED
 #=================================================
@@ -109,6 +115,13 @@ ynh_script_progression --message="Restoring the MySQL database..." --weight=2
 ynh_mysql_setup_db --db_user=$db_user --db_name=$db_name --db_pwd=$db_pwd
 ynh_mysql_connect_as --user=$db_user --password=$db_pwd --database=$db_name < ./db.sql
 
+#=================================================
+# SETUP REDIS DATABASE
+#=================================================
+ynh_script_progression --message="Setup Redis database..." --weight=2
+
+ynh_replace_string --match_string=".*REDIS_URL.*$" --replace_string="REDIS_URL=redis://localhost:6379/$redis_db" --target_file="$config_file"
+
 #=================================================
 # RESTORE SYSTEMD
 #=================================================
diff --git a/scripts/upgrade b/scripts/upgrade
index b4ffdcf..780a40d 100755
--- a/scripts/upgrade
+++ b/scripts/upgrade
@@ -8,6 +8,7 @@
 
 source _common.sh
 source ynh_install_ruby
+source ynh_redis
 source /usr/share/yunohost/helpers
 
 #=================================================
@@ -27,6 +28,9 @@ db_pwd=$(ynh_app_setting_get --app=$app --key=mysqlpwd)
 port=$(ynh_app_setting_get --app=$app --key=port)
 access_domain=$(ynh_app_setting_get --app=$app --key=access_domain)
 mail=$(ynh_app_setting_get --app=$app --key=mail)
+redis_db=$(ynh_app_setting_get --app=$app --key=redis_db)
+
+config_file="$final_path/live/.env"
 
 #=================================================
 # CHECK VERSION
@@ -92,15 +96,21 @@ if [ -z "$mail" ]; then
     ynh_app_setting_set --app=$app --key=mail --value=$mail
 fi
 
+# If redis_db doesn't exist, create it
+if [ -z "$redis_db" ]; then
+    redis_db=$(ynh_redis_get_free_db)
+    ynh_app_setting_set --app=$app --key=redis_db --value="$redis_db"
+fi
+
 if ynh_compare_current_package_version --comparison lt --version "3.13.6~ynh4"
 then
-    # Add Variables to .env config file
+    # Add variables to .env config file
     echo -e "\
-        \n# Public file server\
-        \n# Empty is disabled\
-        \n# Any value is enabled\
-        \nRAILS_SERVE_STATIC_FILES=\
-        " >> "$final_path/live/.env"
+\n# Public file server\
+\n# Empty is disabled\
+\n# Any value is enabled\
+\nRAILS_SERVE_STATIC_FILES=\
+" >> "$config_file"
 
     # Apply Patch
     if [ -f "$YNH_CWD/../sources/patches/app-01-add-mail.patch" ]
@@ -111,6 +121,33 @@ then
     fi
 fi
 
+if ynh_compare_current_package_version --comparison lt --version "3.20.4~ynh1"
+then
+    # Add variables to .env config file
+    echo -e "\
+\n# (Optional) Redis Cache for ephemeral sessions\
+\nREDIS_URL=redis://cache:6379\
+\n\
+\n# (Optional) Change URLs to Internal DNS\
+\n#INTERNAL_DNS_REROUTE_ENABLED=false\
+\n\
+\n# (Optional) Auth Proxy JWT Secret\
+\n#AUTH_JWT_SECRET=changeme123\
+\n\
+\n# (Optional) User Management Server - registration emails, subscriptions etc.\
+\n#USER_MANAGEMENT_SERVER=\
+" >> "$config_file"
+
+    # Change variables to .env config file
+    ynh_replace_string \
+        --match_string="RAILS_LOG_LEVEL=.*$" \
+        --replace_string='# Log Level options: "INFO" | "DEBUG" | "INFO" | "WARN" | "ERROR" | "FATAL"\nRAILS_LOG_LEVEL=INFO' \
+        --target_file="$config_file"
+
+    ynh_replace_string --match_string="REDIS_URL.*$" --replace_string="REDIS_URL=redis://localhost:6379/$redis_db" --target_file="$config_file"
+
+fi
+
 #=================================================
 # STANDARD UPGRADE STEPS
 #=================================================
@@ -233,7 +270,8 @@ then
         exec_as "$app" env PATH=$PATH /opt/rbenv/versions/$RUBY_VERSION/bin/bundle config set path 'vendor/bundle'
         exec_as "$app" env PATH=$PATH /opt/rbenv/versions/$RUBY_VERSION/bin/bundle config set with 'development'
         exec_as "$app" env PATH=$PATH /opt/rbenv/versions/$RUBY_VERSION/bin/bundle install
-        exec_as "$app" env PATH=$PATH RAILS_ENV=production /opt/rbenv/versions/$RUBY_VERSION/bin/bundle exec rails db:create db:migrate --quiet
+        exec_as "$app" env PATH=$PATH RAILS_ENV=production /opt/rbenv/versions/$RUBY_VERSION/bin/bundle exec rails db:migrate --quiet
+        exec_as "$app" env PATH=$PATH RAILS_ENV=production /opt/rbenv/versions/$RUBY_VERSION/bin/bundle exec rails db:seed --quiet
 #        exec_as "$app" env PATH=$PATH RAILS_ENV=production /opt/rbenv/versions/$RUBY_VERSION/bin/bundle exec rails assets:precompile --quiet
     popd
 fi
diff --git a/scripts/ynh_redis b/scripts/ynh_redis
new file mode 100644
index 0000000..5ab83fd
--- /dev/null
+++ b/scripts/ynh_redis
@@ -0,0 +1,39 @@
+#!/bin/bash
+
+# get the first available redis database
+#
+# usage: ynh_redis_get_free_db
+# | returns: the database number to use
+ynh_redis_get_free_db() {
+    local result max db
+    result=$(redis-cli INFO keyspace)
+
+    # get the num
+    max=$(cat /etc/redis/redis.conf | grep ^databases | grep -Eow "[0-9]+")
+
+    db=0
+    # default Debian setting is 15 databases
+    for i in $(seq 0 "$max")
+    do
+        if ! echo "$result" | grep -q "db$i"
+        then
+            db=$i
+            break 1
+        fi
+        db=-1
+    done
+
+    test "$db" -eq -1 && ynh_die --message="No available Redis databases..."
+
+    echo "$db"
+}
+
+# Create a master password and set up global settings
+# Please always call this script in install and restore scripts
+#
+# usage: ynh_redis_remove_db database
+# | arg: database - the database to erase
+ynh_redis_remove_db() {
+    local db=$1
+    redis-cli -n "$db" flushall
+}