diff --git a/Gemfile b/Gemfile
index c38821d..90a6000 100644
--- a/Gemfile
+++ b/Gemfile
@@ -9,7 +9,6 @@ gem 'webpacker', '~> 5.0'
 gem 'turbolinks', '~> 5'
 gem 'jbuilder', '~> 2.7'
 gem 'bootsnap', '>= 1.4.4', require: false
-gem 'puma', '~> 5.0'
 
 group :development, :test do
   gem 'byebug', platforms: [:mri, :mingw, :x64_mingw]
@@ -43,3 +42,5 @@ gem 'will_paginate', '~> 3.0'
 gem 'whenever', '~> 0.9', require: false
 gem 'mysql2', '>=0.5'
 gem 'base32'
+
+gem "webrick", "~> 1.7" # fallback for removed puma; not included in alpine
diff --git a/Gemfile.lock b/Gemfile.lock
index 61d9ed6..a216226 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -127,8 +127,6 @@ GEM
       mini_portile2 (~> 2.6.1)
       racc (~> 1.4)
     public_suffix (4.0.6)
-    puma (5.5.2)
-      nio4r (~> 2.0)
     racc (1.6.0)
     rack (2.2.3)
     rack-mini-profiler (2.3.3)
@@ -232,6 +230,7 @@ GEM
       rack-proxy (>= 0.6.1)
       railties (>= 5.2)
       semantic_range (>= 2.3.0)
+    webrick (1.7.0)
     websocket-driver (0.7.5)
       websocket-extensions (>= 0.1.0)
     websocket-extensions (0.1.5)
@@ -256,7 +255,6 @@ DEPENDENCIES
   listen (~> 3.3)
   midi-smtp-server (~> 3.0)
   mysql2 (>= 0.5)
-  puma (~> 5.0)
   rack-mini-profiler (~> 2.0)
   rails (~> 6.1.4, >= 6.1.4.4)
   roo
@@ -271,6 +269,7 @@ DEPENDENCIES
   web-console (>= 4.1.0)
   webdrivers
   webpacker (~> 5.0)
+  webrick (~> 1.7)
   whenever (~> 0.9)
   will_paginate (~> 3.0)
 
diff --git a/README.md b/README.md
index 058558b..da0723e 100644
--- a/README.md
+++ b/README.md
@@ -5,7 +5,7 @@
 Sharedlists is a simple rails driven database for managing multiple product lists of various suppliers.
 
 This app is used in conjunction with [foodsoft](https://github.com/foodcoops/foodsoft).
-Recommended [Ruby](http://ruby-lang.org/) version is 2.7.
+Recommended [Ruby](http://ruby-lang.org/) version is 2.3 (note that 2.4 does not work).
 
 
 ## Development
@@ -15,7 +15,7 @@ Recommended [Ruby](http://ruby-lang.org/) version is 2.7.
 Copy `config/database.yml.SAMPLE` to `config/database.yml` and
 
     docker-compose run --rm app bundle
-    docker-compose run --rm app rails db:setup
+    docker-compose run --rm app rake db:setup
 
 ### Run
 
@@ -31,8 +31,6 @@ To access sharedlists, you'll need to create a user (and I guess you want admin
     > u.save!
     > exit
 
-You can create more users within the web interface.
-
 ## Production
 
 Either fetch the image, or build it:
@@ -41,16 +39,16 @@ Either fetch the image, or build it:
     # or
     docker build --tag sharedlists:latest --rm .
 
-Then set environment variables `SECRET_KEY_BASE` and `DATABASE_URL` and run:
+Then set environment variables `SECRET_TOKEN` and `DATABASE_URL` and run:
 
     docker run --name sharedlists_web \
-      -e SECRET_KEY_BASE -e DATABASE_URL -e RAILS_FORCE_SSL=false \
+      -e SECRET_TOKEN -e DATABASE_URL -e RAILS_FORCE_SSL=false \
       sharedlists:latest
 
 To run cronjobs, start another instance:
 
     docker run --name sharedlists_cron \
-      -e SECRET_KEY_BASE -e DATABASE_URL \
+      -e SECRET_TOKEN -e DATABASE_URL \
       sharedlists:latest  ./proc-start cron
 
 If you want to process incoming mails, add another instance like the previous,
@@ -99,19 +97,19 @@ Once you have the `sync_ftp_files` task working, you may wish to setup a
 ### Email
 
 Some suppliers send a regular email with an article list in the attachment. For this, an
-email server needs to be run using the rails task `mail:smtp_server`.
+email server needs to be run using the rake task `mail:smtp_server`.
 On production, you may want to run this on localhost on an unprivileged port, with a
 proper [MTA](https://en.wikipedia.org/wiki/Message_transfer_agent) in front that
 does message routing.
 
 To enable this for a certain supplier, tick the checkbox _Update articles by email_. Then
 select a file format to use for importing, and the supplier's email address from which the
-email is sent. If you only want to import mails with a subject that contains a certain
+email is sent. If you only want to import for mails with a subject that contains a certain
 text (e.g. _Articles in week_), fill in the subject field as well.
 
-What email address does the supplier need to send to? Users will find this after initial creating and
-saving the supplier after _Send to_.
+What email address does the supplier need to send to? Users will find this after saving
+the supplier after _Send to_.
 
 This needs setting up of the environment variable `MAILER_DOMAIN`, on which you receive the
-mails. It is allowed to prefix the address, you may want to set the prefix in `MAILER_PREFIX`.
-This is useful when you're running a mail server in front to route mails.
\ No newline at end of file
+emails. It is allowed to prefix the address, you may want to set the prefix in `MAILER_PREFIX`.
+This is useful when you're running an email server in front to route mails.