Redmine

most likely you forgot to update your Gemfile

https://redmine.org/projects/redmine/wiki/RedmineUpgrade

Pavel Rosický wrote in #note-1:

most likely you forgot to update your Gemfile

https://redmine.org/projects/redmine/wiki/RedmineUpgrade

I already did it!

bitnami@debian:/opt/bitnami/redmine$ bundle install
Unknown database adapter `{"adapter"=>"mysql2", "database"=>"bitnami_redmine", "host"=>"127.0.0.1", "username"=>"bn_redmine", "password"=>"77586cf2c43c18d1caaa5213d88ee15a9d04d508d5286276e0d8322698c5b304", "encoding"=>"utf8mb4", "port"=>"3306"}` found in config/database.yml, use Gemfile.local to load your own database gems
Unknown database adapter `{"adapter"=>"mysql2", "database"=>"bitnami_redmine", "host"=>"127.0.0.1", "username"=>"bn_redmine", "password"=>"77586cf2c43c18d1caaa5213d88ee15a9d04d508d5286276e0d8322698c5b304", "encoding"=>"utf8mb4", "port"=>"3306"}` found in config/database.yml, use Gemfile.local to load your own database gems
Bundle complete! 44 Gemfile dependencies, 78 gems now installed.
Gems in the groups 'development' and 'test' were not installed.
Use `bundle info [gemname]` to see where a bundled gem is installed.
bitnami@debian:/opt/bitnami/redmine$

well, these warnings give you some advice on what's wrong
Unknown database adapter `{"adapter"=>"mysql2"...

it seems your config/database.yml looks like this

production:
  adapter:
    adapter: mysql2
    database: db
    host: localhost
    username: root
    password: "" 
    encoding: utf8mb4

which is an invalid config, please double-check it against the example https://github.com/redmine/redmine/blob/master/config/database.yml.example

Pavel Rosický wrote in #note-3:

well, these warnings give you some advice on what's wrong
Unknown database adapter `{"adapter"=>"mysql2"...

it seems your config/database.yml looks like this
[...]

which is an invalid config, please double-check it against the example https://github.com/redmine/redmine/blob/master/config/database.yml.example

Thanks Pavel!

Despite these adapter errors my redmine was working, just not deleting the issues.

I solved my problem adjusting a parameter in Gemfile file:

Was

1. Include database gems for the adapters found in the database
2. configuration file
   require 'erb'
   require 'yaml'
   database_file = File.join(File.dirname(FILE), "config/database.yml")
   if File.exist?(database_file)
   yaml_config = ERB.new(IO.read(database_file)).result
   database_config = YAML.respond_to?(:unsafe_load) ? YAML.unsafe_load(yaml_config) : YAML.load(yaml_config)
   adapters = database_config.values. filter {|c| c['adapter']}.uniq
   if adapters.any?
   adapters.each do |adapter|
   case adapter
   when 'mysql2'
   gem "mysql2", "~> 0.5.0", :platforms => [:mri, :mingw, :x64_mingw]
   gem "with_advisory_lock"
   when /postgresql/
   gem 'pg', '~> 1.5.3', :platforms => [:mri, :mingw, :x64_mingw]
   when /sqlite3/
   gem 'sqlite3', '~> 1.6.0', :platforms => [:mri, :mingw, :x64_mingw]
   when /sqlserver/
   gem "tiny_tds", "~> 2.1.2", :platforms => [:mri, :mingw, :x64_mingw]
   gem "activerecord-sqlserver-adapter", "~> 6.1.0", :platforms => [:mri, :mingw, :x64_mingw]
   else
   warn("Unknown database adapter `#{adapter}` found in config/database.yml, use Gemfile.local to load your own database gems")
   end
   end
   else
   warn("No adapter found in config/database.yml, please configure it first")
   end
   else

Now

1. Include database gems for the adapters found in the database
2. configuration file
   require 'erb'
   require 'yaml'
   database_file = File.join(File.dirname(FILE), "config/database.yml")
   if File.exist?(database_file)
   yaml_config = ERB.new(IO.read(database_file)).result
   database_config = YAML.respond_to?(:unsafe_load) ? YAML.unsafe_load(yaml_config) : YAML.load(yaml_config)
   adapters = database_config.values. filter_map {|c| c['adapter']}.uniq
   if adapters.any?
   adapters.each do |adapter|
   case adapter
   when 'mysql2'
   gem "mysql2", "~> 0.5.0", :platforms => [:mri, :mingw, :x64_mingw]
   gem "with_advisory_lock"
   when /postgresql/
   gem 'pg', '~> 1.5.3', :platforms => [:mri, :mingw, :x64_mingw]
   when /sqlite3/
   gem 'sqlite3', '~> 1.6.0', :platforms => [:mri, :mingw, :x64_mingw]
   when /sqlserver/
   gem "tiny_tds", "~> 2.1.2", :platforms => [:mri, :mingw, :x64_mingw]
   gem "activerecord-sqlserver-adapter", "~> 6.1.0", :platforms => [:mri, :mingw, :x64_mingw]
   else
   warn("Unknown database adapter `#{adapter}` found in config/database.yml, use Gemfile.local to load your own database gems")
   end
   end
   else
   warn("No adapter found in config/database.yml, please configure it first")
   end
   else

I did that "adjustment" because on my first redmine upgrade from 5.0.5 to 5.1.1 was not working due that "filter_map" parameter, and when I removed it my redmine worked. Now I had to remove and issues are being deleted again!

Pavel Rosický wrote in #note-3:

well, these warnings give you some advice on what's wrong
Unknown database adapter `{"adapter"=>"mysql2"...

it seems your config/database.yml looks like this
[...]

which is an invalid config, please double-check it against the example https://github.com/redmine/redmine/blob/master/config/database.yml.example

My config/database.yml

root@debian:/opt/bitnami/redmine# cat config/database.yml
# Default setup is given for MySQL 5.7.7 or later.
# Examples for PostgreSQL, SQLite3 and SQL Server can be found at the end.
# Line indentation must be 2 spaces (no tabs).
production:
  adapter: mysql2
  database: bitnami_redmine
  host: 127.0.0.1
  username: bn_redmine
  password: "77586cf2c43c18d1caaa5213d88ee15a9d04d508d5286276e0d8322698c5b304" 
  # Use "utf8" instead of "utfmb4" for MySQL prior to 5.7.7
  encoding: utf8mb4
  port: "3306" 
root@debian:/opt/bitnami/redmine#

before an upgrade, you should check the software requirements https://redmine.org/projects/redmine/wiki/RedmineInstall#Requirements and if you have issues, revert your modifications first.

Ruby < 2.7 support has been dropped by Redmine #38134 a year ago (and it's EOL since 2022-04-12)

however, if someone tries to do it anyway, I agree that the error message shouldn't be about a missing method.
https://github.com/redmine/redmine/commit/0b6f4c6811a4a4e823674e3bb8b970ee46a9194b#diff-d09ea66f8227784ff4393d88a19836f321c915ae10031d16c93d67e6283ab55fR66
but it's probably too late to change it back...