diff --git a/lib/zabbixapi.rb b/lib/zabbixapi.rb
index 4b9df72..c83ed32 100755
--- a/lib/zabbixapi.rb
+++ b/lib/zabbixapi.rb
@@ -19,6 +19,7 @@
 require 'zabbixapi/classes/maintenance'
 require 'zabbixapi/classes/mediatypes'
 require 'zabbixapi/classes/proxies'
+require 'zabbixapi/classes/proxygroup'
 require 'zabbixapi/classes/problems'
 require 'zabbixapi/classes/roles'
 require 'zabbixapi/classes/screens'
@@ -137,6 +138,10 @@ def proxies
     @proxies ||= Proxies.new(@client)
   end
 
+  # @return [ZabbixApi::Proxygroup]
+  def proxygroup
+    @proxygroup ||= Proxygroup.new(@client)
+  end
   # @return [ZabbixApi::Roles]
   def roles
     @roles ||= Roles.new(@client)
diff --git a/lib/zabbixapi/classes/hosts.rb b/lib/zabbixapi/classes/hosts.rb
index 9d4794f..d2e3665 100755
--- a/lib/zabbixapi/classes/hosts.rb
+++ b/lib/zabbixapi/classes/hosts.rb
@@ -30,7 +30,7 @@ def dump_by_id(data)
             key.to_sym => data[key.to_sym]
           },
           output: 'extend',
-          selectGroups: 'shorten'
+          selectHostGroups: 'extend'
         }
       )
     end
@@ -44,8 +44,7 @@ def default_options
         interfaces: [],
         status: 0,
         available: 1,
-        groups: [],
-        proxy_hostid: nil
+        groups: []
       }
     end
 
diff --git a/lib/zabbixapi/classes/proxies.rb b/lib/zabbixapi/classes/proxies.rb
index 50cf7af..51244e8 100755
--- a/lib/zabbixapi/classes/proxies.rb
+++ b/lib/zabbixapi/classes/proxies.rb
@@ -11,7 +11,7 @@ def method_name
     #
     # @return [String]
     def identify
-      'host'
+      'name'
     end
 
     # Delete Proxy object using Zabbix API
diff --git a/lib/zabbixapi/classes/proxygroup.rb b/lib/zabbixapi/classes/proxygroup.rb
new file mode 100755
index 0000000..e4c58cb
--- /dev/null
+++ b/lib/zabbixapi/classes/proxygroup.rb
@@ -0,0 +1,55 @@
+class ZabbixApi
+  class Proxygroup < Basic
+    # The method name used for interacting with Proxygroup via Zabbix API
+    #
+    # @return [String]
+    def method_name
+      'proxygroup'
+    end
+
+    # The id field name used for identifying specific Proxygroup objects via Zabbix API
+    #
+    # @return [String]
+    def identify
+      'name'
+    end
+
+    # The key field name used for proxygroup objects via Zabbix API
+    #
+    # @return [String]
+    def key
+      'proxy_groupid'
+    end
+
+    # Delete Proxygroup object using Zabbix API
+    #
+    # @param data [Array] Should include array of Proxygroupid's
+    # @raise [ApiError] Error returned when there is a problem with the Zabbix API call.
+    # @raise [HttpError] Error raised when HTTP status from Zabbix Server response is not a 200 OK.
+    # @return [Integer] The Proxygroup object id that was deleted
+    def delete(data)
+      result = @client.api_request(method: 'proxygroup.delete', params: data)
+      result.empty? ? nil : result['proxyids'][0].to_i
+    end
+
+    # Check if a Proxygroup object is readable using Zabbix API
+    #
+    # @param data [Array] Should include array of Proxygroupid's
+    # @raise [ApiError] Error returned when there is a problem with the Zabbix API call.
+    # @raise [HttpError] Error raised when HTTP status from Zabbix Server response is not a 200 OK.
+    # @return [Boolean] Returns true if the given Proxygroupgroup are readable
+    def isreadable(data)
+      @client.api_request(method: 'proxygroup.isreadable', params: data)
+    end
+
+    # Check if a Proxygroup object is writable using Zabbix API
+    #
+    # @param data [Array] Should include array of Proxygroupid's
+    # @raise [ApiError] Error returned when there is a problem with the Zabbix API call.
+    # @raise [HttpError] Error raised when HTTP status from Zabbix Server response is not a 200 OK.
+    # @return [Boolean] Returns true if the given Proxygroup are writable
+    def iswritable(data)
+      @client.api_request(method: 'proxygroup.iswritable', params: data)
+    end
+  end
+end
diff --git a/lib/zabbixapi/client.rb b/lib/zabbixapi/client.rb
index 53c6f28..828508b 100755
--- a/lib/zabbixapi/client.rb
+++ b/lib/zabbixapi/client.rb
@@ -28,7 +28,7 @@ def auth
       api_request(
         method: 'user.login',
         params: {
-          user: @options[:user],
+          username: @options[:user],
           password: @options[:password]
         }
       )
diff --git a/lib/zabbixapi/version.rb b/lib/zabbixapi/version.rb
index 6c3cdc8..c59b15b 100755
--- a/lib/zabbixapi/version.rb
+++ b/lib/zabbixapi/version.rb
@@ -1,3 +1,3 @@
 class ZabbixApi
-  VERSION = '5.0.0-alpha1'.freeze
+  VERSION = '6.0.0-alpha4'.freeze
 end