diff --git a/.ruby-version b/.ruby-version
index b502146..6cb9d3d 100644
--- a/.ruby-version
+++ b/.ruby-version
@@ -1 +1 @@
-3.0.2
+3.4.3
diff --git a/Gemfile.lock b/Gemfile.lock
index 6867842..fa4c1e7 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -2,27 +2,27 @@ PATH
   remote: .
   specs:
     girocode (0.2.0)
-      bank-contact
+      iban-tools
       rqrcode
 
 GEM
   remote: https://rubygems.org/
   specs:
-    bank-contact (0.0.6)
     chunky_png (1.4.0)
-    docile (1.4.0)
-    minitest (5.14.4)
-    rake (13.0.6)
-    rqrcode (2.1.0)
+    docile (1.4.1)
+    iban-tools (1.2.1)
+    minitest (5.25.5)
+    rake (13.3.0)
+    rqrcode (3.1.0)
       chunky_png (~> 1.0)
-      rqrcode_core (~> 1.0)
-    rqrcode_core (1.2.0)
-    simplecov (0.21.2)
+      rqrcode_core (~> 2.0)
+    rqrcode_core (2.0.0)
+    simplecov (0.22.0)
       docile (~> 1.1)
       simplecov-html (~> 0.11)
       simplecov_json_formatter (~> 0.1)
-    simplecov-html (0.12.3)
-    simplecov_json_formatter (0.1.3)
+    simplecov-html (0.13.1)
+    simplecov_json_formatter (0.1.4)
 
 PLATFORMS
   ruby
@@ -34,4 +34,4 @@ DEPENDENCIES
   simplecov
 
 BUNDLED WITH
-   2.2.22
+   2.6.8
diff --git a/girocode.gemspec b/girocode.gemspec
index c8cd13d..e6c480f 100644
--- a/girocode.gemspec
+++ b/girocode.gemspec
@@ -17,5 +17,5 @@ Gem::Specification.new do |s|
   s.require_paths = ['lib']
 
   s.add_dependency 'rqrcode'
-  s.add_dependency 'bank-contact'
+  s.add_dependency 'iban-tools'
 end
diff --git a/lib/girocode.rb b/lib/girocode.rb
index cf1775a..6f8b99a 100644
--- a/lib/girocode.rb
+++ b/lib/girocode.rb
@@ -1,5 +1,5 @@
 require 'bigdecimal'
-require 'bank/contact'
+require 'iban-tools'
 require 'rqrcode'
 
 require_relative 'girocode/version'
diff --git a/lib/girocode/code.rb b/lib/girocode/code.rb
index 9b41b2d..bf2c887 100644
--- a/lib/girocode/code.rb
+++ b/lib/girocode/code.rb
@@ -1,13 +1,13 @@
 module Girocode
   class Error < StandardError; end
-  
+
   class Code
     ATTRIBUTES = %i[bic name iban currency amount purpose creditor_reference reference bto_info]
     attr_reader *ATTRIBUTES
-    
+
     MAX_PAYLOAD_BYTES = 331
     AMOUNT_RANGE = BigDecimal('0.01')..BigDecimal('999999999.99')
-    
+
     def initialize(**attrs)
       if keys = attrs.keys - ATTRIBUTES and not keys.empty?
         raise ArgumentError, "Illegal attributes #{keys.inspect}"
@@ -19,17 +19,17 @@ module Girocode
       raise ArgumentError, "either creditor reference or reference may be set" if creditor_reference? && reference?
       raise ArgumentError, "payload too long" if payload.bytesize > MAX_PAYLOAD_BYTES
     end
-    
+
     def bic=(value)
       if value.nil?
         @bic = nil
+      elsif value.match? /\A[A-Z0-9]{4}([A-Z]{2})([A-Z0-9]{2})([A-Z0-9]{3})?\z/
+        @bic = value
       else
-        bic = Bank::BIC.new(value)
-        raise ArgumentError, "Invalid BIC #{value.inspect}" unless bic.valid?
-        @bic = bic.to_s
+        raise ArgumentError, "Invalid BIC #{value.inspect}"
       end
     end
-    
+
     def name=(value)
       value = value.strip
       raise ArgumentError, 'name is required' unless value
@@ -37,81 +37,81 @@ module Girocode
       raise ArgumentError, 'Illegal name' if value.include?("\n") || value.include?("\r")
       @name = value
     end
-    
+
     def iban=(value)
-      iban = Bank::IBAN.new(value)
-      raise ArgumentError, "Invalid IBAN #{value.inspect}" unless iban.valid?
-      @iban = iban.to_s
+      raise ArgumentError, "Invalid IBAN #{value.inspect}" unless IBANTools::IBAN.valid?(value)
+
+      @iban = value
     end
-    
+
     def currency=(value)
       value = value.to_s.upcase
       raise ArgumentError, "Invalid currency" unless value.match?(/\A[A-Z]{3}\z/)
       @currency = value
     end
-    
+
     def amount=(value)
       raise ArgumentError, 'amount is required' unless value
       value = BigDecimal(value, Float::DIG + 1)
       raise ArgumentError, "invalid amount #{value.inspect}" unless AMOUNT_RANGE.cover?(value)
       @amount = value
     end
-    
+
     def purpose=(value)
       unless value.nil?
         raise ArgumentError, "invalid purpose #{value.inspect}" unless value.match?(/\A[A-z0-9]{0,4}\z/)
       end
       @purpose = value
     end
-    
+
     def creditor_reference=(value)
       unless value.nil?
         raise ArgumentError, "invalid creditor reference #{value.inspect}" if value.include?("\n") || value.include?("\r") || value.size > 35
       end
       @creditor_reference = value
     end
-    
+
     def reference=(value)
       unless value.nil?
         raise ArgumentError, "invalid reference #{value.inspect}" if value.include?("\n") || value.include?("\r") || value.size > 140
       end
       @reference = value
     end
-    
+
     def bto_info=(value)
       unless value.nil?
         raise ArgumentError, "invalid bto_info #{value.inspect}" if value.include?("\n") || value.include?("\r") || value.size > 70
       end
       @bto_info = value
     end
-    
+
     ATTRIBUTES.each do |attr|
       define_method("#{attr}?") do
         value = instance_variable_get("@#{attr}")
         value.respond_to?(:empty?) ? !value.empty? : !!value
       end
     end
-    
+
     def payload
       ['BCD', '002', '1', 'SCT',
        bic, name, iban,formatted_amount, purpose,
        creditor_reference || reference, bto_info].map(&:to_s).join("\n")
     end
-    
+
     def to_qrcode
       RQRCode::QRCode.new(payload, level: :m, mode: :byte_8bit)
     end
-    
+
     def to_ascii
       to_qrcode.to_s
     end
-    
+
     %i[png svg html ansi].each do |format|
       define_method("to_#{format}") { |*args| to_qrcode.public_send("as_#{format}", *args) }
     end
-    
+
     private
-    
+
     def formatted_amount
       "#{currency}#{amount.round(2).to_s('F')}" if currency? && amount
     end