diff --git a/README.md b/README.md
index 1779a2ea..b6d5ae36 100644
--- a/README.md
+++ b/README.md
@@ -1,7 +1,7 @@
 Redmine DMSF Plugin
 ===================
 
-The current version of Redmine DMSF is **1.6.0** [![Build Status](https://api.travis-ci.org/danmunn/redmine_dmsf.png)](https://travis-ci.org/danmunn/redmine_dmsf)
+The current version of Redmine DMSF is **1.6.1 devel** [![Build Status](https://api.travis-ci.org/danmunn/redmine_dmsf.png)](https://travis-ci.org/danmunn/redmine_dmsf)
 
 Redmine DMSF is Document Management System Features plugin for Redmine issue tracking system; It is aimed to replace current Redmine's Documents module.
 
diff --git a/app/controllers/dmsf_files_controller.rb b/app/controllers/dmsf_files_controller.rb
index 67122f04..2c31a203 100644
--- a/app/controllers/dmsf_files_controller.rb
+++ b/app/controllers/dmsf_files_controller.rb
@@ -114,8 +114,8 @@ class DmsfFilesController < ApplicationController
         revision.minor_version = last_revision.minor_version
         version = params[:version].to_i
         if version == 3
-          revision.major_version = params[:custom_version_major].to_i
-          revision.minor_version = params[:custom_version_minor].to_i
+          revision.major_version = DmsfUploadHelper::db_version(params[:custom_version_major])
+          revision.minor_version = DmsfUploadHelper::db_version(params[:custom_version_minor])
         else
            revision.increase_version(version)
         end
diff --git a/app/helpers/dmsf_upload_helper.rb b/app/helpers/dmsf_upload_helper.rb
index 7639cd97..f8fab061 100644
--- a/app/helpers/dmsf_upload_helper.rb
+++ b/app/helpers/dmsf_upload_helper.rb
@@ -72,8 +72,8 @@ module DmsfUploadHelper
           version = 1
         end
         if version == 3
-          new_revision.major_version = commited_file[:custom_version_major].to_i
-          new_revision.minor_version = commited_file[:custom_version_minor].to_i
+          new_revision.major_version = DmsfUploadHelper::db_version(commited_file[:custom_version_major])
+          new_revision.minor_version = DmsfUploadHelper::db_version(commited_file[:custom_version_minor])
         else
           new_revision.increase_version(version)
         end
@@ -162,4 +162,54 @@ module DmsfUploadHelper
     [files, failed_uploads]
   end
 
+  # 0..99, A..Z except O
+  def self.major_version_select_options
+    (0..99).to_a + ('A'..'Y').to_a - ['O']
+  end
+
+  # 0..99, ' '
+  def self.minor_version_select_options
+    (0..99).to_a + [' ']
+  end
+
+  # 1 -> 2, -1 -> -2, A -> B
+  def self.increase_version(version, number)
+    return number if ((version == ' ') || ((-version) == ' '.ord))
+    if Integer(version)
+      if version >= 0
+        if (version + number) < 100
+          version + number
+        else
+          version
+        end
+      else
+        if -(version - number) < 'Z'.ord
+          version - number
+        else
+          version
+        end
+      end
+    end
+    rescue
+      if (version.ord + number) < 'Z'.ord
+        (version.ord + number).chr
+      else
+        version
+      end
+  end
+
+  # 1 -> 1, -65 -> A
+  def self.gui_version(version)
+    return version if version >= 0
+    (-version).chr
+  end
+
+  # 1 -> 1, A -> -65
+  def self.db_version(version)
+    version.to_i if Integer(version)
+  rescue
+    version = ' ' if version.blank?
+    -(version.ord)
+  end
+
 end
diff --git a/app/models/dmsf_file_revision.rb b/app/models/dmsf_file_revision.rb
index 8c609624..55439ebf 100644
--- a/app/models/dmsf_file_revision.rb
+++ b/app/models/dmsf_file_revision.rb
@@ -131,7 +131,11 @@ class DmsfFileRevision < ActiveRecord::Base
   end
 
   def version
-    "#{self.major_version}.#{self.minor_version}"
+    ver = DmsfUploadHelper::gui_version(self.major_version).to_s
+    if -self.minor_version != ' '.ord
+      ver << ".#{DmsfUploadHelper::gui_version(self.minor_version)}"
+    end
+    ver
   end
   
   def storage_base_path
@@ -233,7 +237,7 @@ class DmsfFileRevision < ActiveRecord::Base
   def increase_version(version_to_increase)
     self.minor_version = case version_to_increase
       when 1
-        self.minor_version + 1
+        DmsfUploadHelper.increase_version(self.minor_version, 1)
       when 2
         0
       else
@@ -241,7 +245,7 @@ class DmsfFileRevision < ActiveRecord::Base
     end
     self.major_version = case version_to_increase
       when 2
-        self.major_version + 1
+        DmsfUploadHelper::increase_version(self.major_version, 1)
       else
         major_version
     end
diff --git a/app/views/dmsf_files/_file_new_revision.html.erb b/app/views/dmsf_files/_file_new_revision.html.erb
index b1a44be8..7c8f1ebf 100644
--- a/app/views/dmsf_files/_file_new_revision.html.erb
+++ b/app/views/dmsf_files/_file_new_revision.html.erb
@@ -58,19 +58,21 @@
             <p>
               <%= label_tag('version_0', l(:label_dmsf_version)) %>
               <%= radio_button_tag('version', 0, @revision.version == @file.last_revision.version) %>
-              <%= @file.last_revision.major_version %>.<%= @file.last_revision.minor_version %>
+              <%= @file.last_revision.version %>
               <%= l(:option_version_same) %><br/>
               <%= radio_button_tag('version', 1, @revision.major_version == @file.last_revision.major_version && @revision.minor_version != @file.last_revision.minor_version) %> 
-              <%= @file.last_revision.major_version %>.<%= @file.last_revision.minor_version + 1 %>
+              <%= DmsfUploadHelper::gui_version(@file.last_revision.major_version) %>.<%= DmsfUploadHelper::gui_version(DmsfUploadHelper.increase_version(@file.last_revision.minor_version, 1)) %>
               <%= l(:option_version_minor) %><br/>
               <%= radio_button_tag('version', 2, @revision.major_version != @file.last_revision.major_version) %> 
-              <%= @file.last_revision.major_version + 1 %>.0 
+              <%= DmsfUploadHelper.gui_version(DmsfUploadHelper::increase_version(@file.last_revision.major_version, 1)) %>.0
               <%= l(:option_version_major) %><br/>
               <%= radio_button_tag('version', 3) %>        
-              <%= select_tag 'custom_version_major', options_for_select(0..99, @file.last_revision.major_version + 2),
-                             :onchange => '$("#version_3").prop("checked", true)', :class => 'dmsf_select_version' %>.
-              <%= select_tag 'custom_version_minor', options_for_select(0..99, @file.last_revision.minor_version + 1),
-                             :onchange => '$("#version_3").prop("checked", true)', :class => 'dmsf_select_version' %>
+              <%= select_tag 'custom_version_major', options_for_select(DmsfUploadHelper::major_version_select_options,
+                    DmsfUploadHelper::gui_version(DmsfUploadHelper::increase_version(@file.last_revision.major_version, 2))),
+                    :onchange => '$("#version_3").prop("checked", true)', :class => 'dmsf_select_version' %>.
+              <%= select_tag 'custom_version_minor', options_for_select(DmsfUploadHelper::minor_version_select_options,
+                    DmsfUploadHelper::gui_version(DmsfUploadHelper.increase_version(@file.last_revision.minor_version, 1))),
+                    :onchange => '$("#version_3").prop("checked", true)', :class => 'dmsf_select_version' %>
               <%= l(:option_version_custom) %>
             </p>
           </div>
diff --git a/app/views/dmsf_files/show.api.rsb b/app/views/dmsf_files/show.api.rsb
index 8f2243b5..99760e9a 100644
--- a/app/views/dmsf_files/show.api.rsb
+++ b/app/views/dmsf_files/show.api.rsb
@@ -4,7 +4,7 @@ api.dmsf_file do
   api.project_id @file.project_id
   api.dmsf_folder_id @file.dmsf_folder_id if @file.dmsf_folder_id
   if @file.last_revision
-    api.version "#{@file.last_revision.major_version}.#{@file.last_revision.minor_version}"
+    api.version "#{@file.last_revision.version}"
     api.mime_type @file.last_revision.mime_type
     api.digest @file.last_revision.digest
     api.size @file.last_revision.size
diff --git a/app/views/dmsf_files/show.html.erb b/app/views/dmsf_files/show.html.erb
index 9dd32195..4007fe73 100644
--- a/app/views/dmsf_files/show.html.erb
+++ b/app/views/dmsf_files/show.html.erb
@@ -117,7 +117,7 @@
           <% end %>
           <div class="status attribute">
             <%= content_tag :div, l(:label_dmsf_version), :class => 'label' %>
-            <%= content_tag :div, "#{revision.major_version}.#{revision.minor_version}", :class => 'value' %>
+            <%= content_tag :div, "#{revision.version}", :class => 'value' %>
           </div>
           <div class="status attribute">
             <%= content_tag :div, l(:label_size), :class => 'label' %>
diff --git a/app/views/dmsf_mailer/files_deleted.html.erb b/app/views/dmsf_mailer/files_deleted.html.erb
index 99a10951..b16d2ea9 100644
--- a/app/views/dmsf_mailer/files_deleted.html.erb
+++ b/app/views/dmsf_mailer/files_deleted.html.erb
@@ -24,7 +24,7 @@
   <p>
     <%= h(file.dmsf_path_str) %> (<%= file.name %>)
     <%  if file.last_revision %>
-      , <%= number_to_human_size(file.last_revision.size) %>, <%= l(:label_dmsf_version) %> <%= file.last_revision.major_version %>.<%= file.last_revision.minor_version %>
+      , <%= number_to_human_size(file.last_revision.size) %>, <%= l(:label_dmsf_version) %> <%= file.last_revision.version %>
     <% end  %>
   </p>
 <% end %>
\ No newline at end of file
diff --git a/app/views/dmsf_mailer/files_deleted.text.erb b/app/views/dmsf_mailer/files_deleted.text.erb
index 5a6fd884..04365cd0 100644
--- a/app/views/dmsf_mailer/files_deleted.text.erb
+++ b/app/views/dmsf_mailer/files_deleted.text.erb
@@ -25,6 +25,6 @@
 <% @files.each do |file| %>  
   <%= h(file.dmsf_path_str) %> (<%= file.name %>)
   <%  if file.last_revision %>
-    , <%= number_to_human_size(file.last_revision.size) %>, <%= l(:label_dmsf_version) %> <%= file.last_revision.major_version %>.<%= file.last_revision.minor_version %>
+    , <%= number_to_human_size(file.last_revision.size) %>, <%= l(:label_dmsf_version) %> <%= file.last_revision.version %>
   <% end  %>  
 <% end %>
\ No newline at end of file
diff --git a/app/views/dmsf_mailer/files_updated.html.erb b/app/views/dmsf_mailer/files_updated.html.erb
index 05b2020a..eeb99d7e 100644
--- a/app/views/dmsf_mailer/files_updated.html.erb
+++ b/app/views/dmsf_mailer/files_updated.html.erb
@@ -26,7 +26,7 @@
     dmsf_file_url(file, :download => '')) %> 
   (<%= file.name %>),
   <%= number_to_human_size(file.last_revision.size) %>,
-  <%= l(:label_dmsf_version) %> <%= file.last_revision.major_version %>.<%= file.last_revision.minor_version %>,
+  <%= l(:label_dmsf_version) %> <%= file.last_revision.version %>,
   <%= "#{file.last_revision.workflow_str(true)}," if file.last_revision.workflow_str(true) != l(:title_none) %>
   <%= link_to(l(:link_details, :title => h(file.title)),
     dmsf_file_url(file)) %>    
diff --git a/app/views/dmsf_mailer/files_updated.text.erb b/app/views/dmsf_mailer/files_updated.text.erb
index de0d8d9f..da8a7082 100644
--- a/app/views/dmsf_mailer/files_updated.text.erb
+++ b/app/views/dmsf_mailer/files_updated.text.erb
@@ -23,7 +23,7 @@
 <% @files.each do |file| %>
   <%= h(file.dmsf_path_str) %> (<%= file.name %>),  
   <%= number_to_human_size(file.last_revision.size) %>,
-  <%= l(:label_dmsf_version) %> <%= file.last_revision.major_version %>.<%= file.last_revision.minor_version %>,
+  <%= l(:label_dmsf_version) %> <%= file.last_revision.version %>,
   <%= "#{file.last_revision.workflow_str(true)}," if file.last_revision.workflow_str(true) != l(:title_none) %>
   <%= dmsf_file_url(file) %>    
   <% if file.last_revision.comment.present? %>
diff --git a/app/views/dmsf_upload/_upload_file.html.erb b/app/views/dmsf_upload/_upload_file.html.erb
index 2311378f..b6a7b3cc 100644
--- a/app/views/dmsf_upload/_upload_file.html.erb
+++ b/app/views/dmsf_upload/_upload_file.html.erb
@@ -59,18 +59,20 @@
       <p>
         <%= label_tag("commited_files[#{i}][version]_minor", l(:label_dmsf_version)) %>
         <%= radio_button_tag("commited_files[#{i}][version]", 1, true) %>
-        <%= upload.major_version %>.<%= upload.minor_version + 1 %>
+        <%= DmsfUploadHelper::gui_version(upload.major_version) %>.<%= DmsfUploadHelper::gui_version(DmsfUploadHelper.increase_version(upload.minor_version, 1)) %>
         <%= l(:option_version_minor) %><br/>
         <%= radio_button_tag("commited_files[#{i}][version]", 2) %>
-        <%= upload.major_version + 1 %>.0
+        <%= DmsfUploadHelper::gui_version(DmsfUploadHelper::increase_version(upload.major_version, 1)) %>.0
         <%= l(:option_version_major) %><br/>
         <%= radio_button_tag("commited_files[#{i}][version]", 3) %>
         <%= select_tag "commited_files[#{i}][custom_version_major]",
-                       options_for_select(0..99, upload.major_version + 2),
+                       options_for_select(DmsfUploadHelper::major_version_select_options,
+                                          DmsfUploadHelper::gui_version(DmsfUploadHelper::increase_version(upload.major_version, 2))),
                        :onchange => "$('#commited_files_#{i}_version_3').prop('checked', true)",
                        :class => 'dmsf_select_version'%>.
         <%= select_tag "commited_files[#{i}][custom_version_minor]",
-                       options_for_select(0..99, upload.minor_version + 1),
+                       options_for_select(DmsfUploadHelper::minor_version_select_options,
+                       DmsfUploadHelper::gui_version(DmsfUploadHelper.increase_version(upload.minor_version, 1))),
                        :onchange => "$('#commited_files_#{i}_version_3').prop('checked', true)",
                        :class => 'dmsf_select_version' %>
         <%= l(:option_version_custom) %>
diff --git a/app/views/dmsf_upload/_upload_file_locked.html.erb b/app/views/dmsf_upload/_upload_file_locked.html.erb
index 61a533c1..65da7655 100644
--- a/app/views/dmsf_upload/_upload_file_locked.html.erb
+++ b/app/views/dmsf_upload/_upload_file_locked.html.erb
@@ -66,7 +66,7 @@
     <div class="splitcontentleft">
       <p>
         <%= label_tag('', l(:label_dmsf_version)) %>
-        <%= text_field_tag(:name, "#{upload.major_version}.#{upload.minor_version}", :readonly => true) %>
+        <%= text_field_tag(:name, "#{DmsfUploadHelper::gui_version(upload.major_version)}.#{DmsfUploadHelper::gui_version(upload.minor_version)}", :readonly => true) %>
       </p>
     </div>
     <div class="splitcontentright">
diff --git a/app/views/dmsf_upload/upload_files.html.erb b/app/views/dmsf_upload/upload_files.html.erb
index 580070f5..1c8fe5ad 100644
--- a/app/views/dmsf_upload/upload_files.html.erb
+++ b/app/views/dmsf_upload/upload_files.html.erb
@@ -42,7 +42,6 @@
       <%= render(:partial => 'upload_file', :locals => {:upload => upload, :i => i}) %>
     <% end %>
   <% end %>
-  <%#= submit_tag l(:submit_commit) %>
   <div class="form-actions">
     <%= submit_tag l(:submit_commit), :class => 'button-positive' %>
   </div>
diff --git a/init.rb b/init.rb
index 3fb93f93..f311d0f2 100644
--- a/init.rb
+++ b/init.rb
@@ -32,7 +32,7 @@ Redmine::Plugin.register :redmine_dmsf do
   end
   author 'Vít Jonáš / Daniel Munn / Karel Pičman'
   description 'Document Management System Features'
-  version '1.6.0'
+  version '1.6.1 devel'
 
   requires_redmine :version_or_higher => '3.4.0'
 
diff --git a/test/integration/rest_api/dmsf_file_api_test.rb b/test/integration/rest_api/dmsf_file_api_test.rb
index d14b96aa..da21152d 100644
--- a/test/integration/rest_api/dmsf_file_api_test.rb
+++ b/test/integration/rest_api/dmsf_file_api_test.rb
@@ -62,7 +62,7 @@ class DmsfFileApiTest < RedmineDmsf::Test::IntegrationTest
     assert_select 'dmsf_file > id', :text => @file1.id.to_s
     assert_select 'dmsf_file > name', :text => @file1.name
     assert_select 'dmsf_file > project_id', :text => @file1.project_id.to_s
-    assert_select 'dmsf_file > version', :text => "#{@file1.last_revision.major_version}.#{@file1.last_revision.minor_version}"
+    assert_select 'dmsf_file > version', :text => "#{@file1.last_revision.version}"
     assert_select 'dmsf_file > mime_type', :text => @file1.last_revision.mime_type
     assert_select 'dmsf_file > digest', :text => @file1.last_revision.digest
     assert_select 'dmsf_file > size', :text => @file1.last_revision.size.to_s
diff --git a/test/unit/dmsf_file_revision_test.rb b/test/unit/dmsf_file_revision_test.rb
index 9231ba3a..50fbebac 100644
--- a/test/unit/dmsf_file_revision_test.rb
+++ b/test/unit/dmsf_file_revision_test.rb
@@ -146,4 +146,16 @@ class DmsfFileRevisionTest < RedmineDmsf::Test::UnitTest
     assert_equal 'John Smith', @revision2.workflow_tooltip
   end
 
+  def test_version
+    @revision1.major_version = 1
+    @revision1.minor_version = 0
+    assert_equal '1.0', @revision1.version
+    @revision1.major_version = -('A'.ord)
+    @revision1.minor_version = -(' '.ord)
+    assert_equal 'A', @revision1.version
+    @revision1.major_version = -('A'.ord)
+    @revision1.minor_version = 0
+    assert_equal 'A.0', @revision1.version
+  end
+
 end
\ No newline at end of file