diff --git a/application/controllers/Config.php b/application/controllers/Config.php
index 2544010b6..0dce618ae 100644
--- a/application/controllers/Config.php
+++ b/application/controllers/Config.php
@@ -10,6 +10,7 @@ class Config extends Secure_Controller
 
 		$this->load->library('barcode_lib');
 		$this->load->library('sale_lib');
+		$this->load->library('tax_lib');
 	}
 
 	/*
@@ -267,6 +268,9 @@ class Config extends Secure_Controller
 
 	public function save_general()
 	{
+		$migrate_sales_history = $this->input->post('migrate_sales_history') != NULL;
+		$migrate_sales_history_block = $this->input->post('migrate_sales_history_block');
+
 		$batch_save_data = array(
 			'theme' => $this->input->post('theme'),
 			'default_tax_1_rate' => parse_decimals($this->input->post('default_tax_1_rate')),
@@ -275,6 +279,8 @@ class Config extends Secure_Controller
 			'default_tax_2_name' => $this->input->post('default_tax_2_name'),
 			'tax_included' => $this->input->post('tax_included') != NULL,
 			'customer_sales_tax_support' => $this->input->post('customer_sales_tax_support') != NULL,
+			'migrate_sales_history' => $migrate_sales_history,
+			'migrate_sales_history_block' => $migrate_sales_history_block,
 			'default_origin_tax_code' => $this->input->post('default_origin_tax_code'),
 			'receiving_calculate_average_price' => $this->input->post('receiving_calculate_average_price') != NULL,
 			'lines_per_page' => $this->input->post('lines_per_page'),
@@ -298,10 +304,47 @@ class Config extends Secure_Controller
 		$result = $this->Appconfig->batch_save($batch_save_data);
 		$success = $result ? TRUE : FALSE;
 
-		echo json_encode(array(
-			'success' => $success,
-			'message' => $this->lang->line('config_saved_' . ($success ? '' : 'un') . 'successfully')
-		));
+		if($success && $migrate_sales_history)
+		{
+			$number_of_unmigrated = $this->Sale->get_count_of_unmigrated();
+			if ($number_of_unmigrated > 0 && $migrate_sales_history_block > 0)
+			{
+				$unmigrated_invoices = $this->Sale->get_unmigrated($migrate_sales_history_block)->result_array();
+
+				foreach($unmigrated_invoices as $key=>$unmigrated_invoice)
+				{
+					$this->tax_lib->upgrade_tax_history_for_sale($unmigrated_invoice['sale_id']);
+				}
+
+				if($migrate_sales_history_block > $number_of_unmigrated)
+				{
+					$migrate_sales_history_block = $number_of_unmigrated;
+				}
+
+				$number_of_unmigrated = $this->Sale->get_count_of_unmigrated();
+
+				echo json_encode(array(
+					'success' => $success,
+					'message' => $this->lang->line('config_saved_with_migration').' '.$migrate_sales_history_block.' / '.$number_of_unmigrated.' '.$this->lang->line('config_migrate_remaining')
+				));
+
+			}
+			else
+			{
+				echo json_encode(array(
+					'success' => $success,
+					'message' => $this->lang->line('config_saved_' . ($success ? '' : 'un') . 'successfully')
+				));
+			}
+		}
+		else
+		{
+			echo json_encode(array(
+				'success' => $success,
+				'message' => $this->lang->line('config_saved_' . ($success ? '' : 'un') . 'successfully')
+			));
+		}
+
 	}
 
 	public function check_number_locale()
diff --git a/application/language/en/config_lang.php b/application/language/en/config_lang.php
index d5e7a152e..0ff09c371 100644
--- a/application/language/en/config_lang.php
+++ b/application/language/en/config_lang.php
@@ -154,6 +154,10 @@ $lang["config_mailchimp_key_successfully"] = "Valid API Key";
 $lang["config_mailchimp_key_unsuccessfully"] = "Invalid API Key";
 $lang["config_message"] = "Message";
 $lang["config_message_configuration"] = "Message Configuration";
+$lang["config_migrate_remaining"] = "remaining to be migrated";
+$lang["config_migrate_sales_history"] = "Migrate sales history on Save";
+$lang["config_migrate_sales_history_block"] = "Sales to migrate per Save";
+$lang["config_saved_with_migration"] = "Configuration saved and the number of sales migrated is ";
 $lang["config_msg_msg"] = "Saved Text Message";
 $lang["config_msg_msg_placeholder"] = "If you wish to use a SMS template save your message here. Otherwise leave the box blank.";
 $lang["config_msg_pwd"] = "SMS-API Password";
diff --git a/application/libraries/Tax_lib.php b/application/libraries/Tax_lib.php
index 0718dbb9d..e8ea75456 100644
--- a/application/libraries/Tax_lib.php
+++ b/application/libraries/Tax_lib.php
@@ -89,35 +89,32 @@ class Tax_lib
 
 		$tax_group_index = $this->clean('X'.$tax_group);
 
-		if ($item_tax_amount != 0)
+		if(!array_key_exists($tax_group_index, $sales_taxes))
 		{
-			if(!array_key_exists($tax_group_index, $sales_taxes))
-			{
-				$insertkey = $tax_group_index;
+			$insertkey = $tax_group_index;
 
-				$sales_tax = array($insertkey => array(
-					'sale_id' => $sale_id,
-					'tax_type' => $tax_type,
-					'tax_group' => $tax_group,
-					'sale_tax_basis' => $tax_basis,
-					'sale_tax_amount' => $item_tax_amount,
-					'print_sequence' => $tax_group_sequence,
-					'name' => $name,
-					'tax_rate' => $tax_rate,
-					'sales_tax_code' => $tax_code,
-					'rounding_code' => $rounding_code
-				));
+			$sales_tax = array($insertkey => array(
+				'sale_id' => $sale_id,
+				'tax_type' => $tax_type,
+				'tax_group' => $tax_group,
+				'sale_tax_basis' => $tax_basis,
+				'sale_tax_amount' => $item_tax_amount,
+				'print_sequence' => $tax_group_sequence,
+				'name' => $name,
+				'tax_rate' => $tax_rate,
+				'sales_tax_code' => $tax_code,
+				'rounding_code' => $rounding_code
+			));
 
-				//add to existing array
-				$sales_taxes += $sales_tax;
-			}
-			else
-			{
-				// Important ... the sales amounts are accumulated for the group at the maximum configurable scale value of 4
-				// but the scale will in reality be the scale specified by the tax_decimal configuration value  used for sales_items_taxes
-				$sales_taxes[$tax_group_index]['sale_tax_basis'] = bcadd($sales_taxes[$tax_group_index]['sale_tax_basis'], $tax_basis, 4);
-				$sales_taxes[$tax_group_index]['sale_tax_amount'] = bcadd($sales_taxes[$tax_group_index]['sale_tax_amount'], $item_tax_amount, 4);
-			}
+			//add to existing array
+			$sales_taxes += $sales_tax;
+		}
+		else
+		{
+			// Important ... the sales amounts are accumulated for the group at the maximum configurable scale value of 4
+			// but the scale will in reality be the scale specified by the tax_decimal configuration value  used for sales_items_taxes
+			$sales_taxes[$tax_group_index]['sale_tax_basis'] = bcadd($sales_taxes[$tax_group_index]['sale_tax_basis'], $tax_basis, 4);
+			$sales_taxes[$tax_group_index]['sale_tax_amount'] = bcadd($sales_taxes[$tax_group_index]['sale_tax_amount'], $item_tax_amount, 4);
 		}
 	}
 
@@ -318,6 +315,45 @@ class Tax_lib
 
 		return preg_replace('/[^A-Za-z0-9\-]/', '', $string); // Removes special chars.
 	}
-}
 
-?>
+	function upgrade_tax_history_for_sale($sale_id)
+	{
+		$tax_decimals = $this->CI->config->config['tax_decimals'];
+		$tax_included = $this->CI->config->config['tax_included'];
+
+		if($tax_included)
+		{
+			$tax_type = Tax_lib::TAX_TYPE_VAT;
+		}
+		else
+		{
+			$tax_type = Tax_lib::TAX_TYPE_SALES;
+		}
+
+		$sales_taxes = array();
+		$tax_group_sequence = 0;
+
+		$items = $this->CI->Sale->get_sale_items_for_migration($sale_id)->result_array();
+		foreach($items as $item)
+		{
+			// This computes tax for each line item and adds it to the tax type total
+			$tax_group = (float)$item['percent'] . '% ' . $item['name'];
+			$tax_basis = $this->CI->sale_lib->get_item_total($item['quantity_purchased'], $item['item_unit_price'], $item['discount_percent'], TRUE);
+			$item_tax_amount = 0;
+
+			if($tax_included)
+			{
+				$item_tax_amount = $this->CI->sale_lib->get_item_tax($item['quantity_purchased'], $item['item_unit_price'], $item['discount_percent'], $item['percent']);
+			}
+			else
+			{
+				$item_tax_amount = $this->get_sales_tax_for_amount($tax_basis, $item['percent'], '0', $tax_decimals);
+			}
+			$this->CI->Sale->update_sales_items_taxes_amount($sale_id, $item['line'], $item['name'], $item['percent'], $tax_type, $item_tax_amount);
+			$this->update_sales_taxes($sales_taxes, $tax_type, $tax_group, $item['percent'], $tax_basis, $item_tax_amount, $tax_group_sequence, '0', $sale_id, $item['name']);
+			$tax_group_sequence += 1;
+		}
+		$this->CI->Sale->save_sales_tax($sales_taxes);
+	}
+}
+?>
\ No newline at end of file
diff --git a/application/models/Sale.php b/application/models/Sale.php
index b361407cd..87f9d4f5a 100644
--- a/application/models/Sale.php
+++ b/application/models/Sale.php
@@ -752,11 +752,14 @@ class Sale extends CI_Model
 		}
 	}
 
-	private function save_sales_tax(&$sales_taxes)
+	public function save_sales_tax(&$sales_taxes)
 	{
+		error_log('>>>Sale.save_sales_tax started'.print_r($sales_taxes, TRUE));
 		foreach($sales_taxes as $line=>$sales_tax)
 		{
+			error_log('>>>Sale.save_sales_tax $sales_tax - '.print_r($sales_tax, TRUE));
 			$this->db->insert('sales_taxes', $sales_tax);
+			error_log('>>>Sale.save_sales_tax sales_tax written');
 		}
 	}
 
@@ -1205,5 +1208,63 @@ class Sale extends CI_Model
 
 		return $this->db->get();
 	}
+
+	public function get_sale_items_for_migration($sale_id)
+	{
+
+		$this->db->select('sales_items.sale_id as sale_id');
+		$this->db->select('sales_items.line as line');
+		$this->db->select('item_unit_price');
+		$this->db->select('discount_percent');
+		$this->db->select('quantity_purchased');
+		$this->db->select('percent');
+		$this->db->select('name');
+		$this->db->from('sales_items as sales_items');
+		$this->db->join('sales_items_taxes as sales_items_taxes', 'sales_items.sale_id = sales_items_taxes.sale_id and sales_items.line = sales_items_taxes.line');
+		$this->db->where('sales_items.sale_id', $sale_id);
+
+		return $this->db->get();
+	}
+
+	public function get_count_of_unmigrated()
+	{
+		$result = $this->db->query('SELECT COUNT(*) FROM(SELECT SIT.sale_id, ST.sale_id as sales_taxes_sale_id FROM '
+			. $this->db->dbprefix('sales_items_taxes')
+			. ' as SIT LEFT JOIN '
+			. $this->db->dbprefix('sales_taxes')
+			. ' as ST ON SIT.sale_id = ST.sale_id WHERE ST.sale_id is null GROUP BY SIT.sale_id, ST.sale_id'
+			. ' ORDER BY SIT.sale_id) as US')->result_array();
+
+		return $result[0]['COUNT(*)'];
+	}
+
+	public function get_unmigrated($block_count)
+	{
+
+		$this->db->select('SIT.sale_id');
+		$this->db->select('ST.sale_id as sales_taxes_sale_id');
+		$this->db->from('sales_items_taxes as SIT');
+		$this->db->join('sales_taxes as ST','SIT.sale_id = ST.sale_id', 'left');
+		$this->db->where('ST.sale_id is null');
+		$this->db->group_by('SIT.sale_id');
+		$this->db->group_by('ST.sale_id');
+		$this->db->order_by('SIT.sale_id');
+		$this->db->limit($block_count);
+		$query = $this->db->get();
+
+		return $query;
+
+	}
+
+	public function update_sales_items_taxes_amount($sale_id, $line, $name, $percent, $tax_type, $item_tax_amount)
+	{
+		error_log('>>>Sale.update_sales_items_taxes_amount '.$sale_id.', '.$line.', '.$name.', '.$percent.', '.$tax_type.', '.$item_tax_amount);
+		$this->db->where('sale_id', $sale_id);
+		$this->db->where('line', $line);
+		$this->db->where('name', $name);
+		$this->db->where('percent', $percent);
+		$this->db->update('sales_items_taxes', array('tax_type' => $tax_type, 'item_tax_amount' => $item_tax_amount));
+	}
+
 }
-?>
+?>
\ No newline at end of file
diff --git a/application/views/configs/general_config.php b/application/views/configs/general_config.php
index 0c4ad8c25..c30d3a803 100644
--- a/application/views/configs/general_config.php
+++ b/application/views/configs/general_config.php
@@ -82,7 +82,31 @@
 				</div>
 			</div>
 
-			<div class="form-group form-group-sm">
+
+            <div class="form-group form-group-sm">
+				<?php echo form_label($this->lang->line('config_migrate_sales_history'), 'migrate_sales_history', array('class' => 'control-label col-xs-2')); ?>
+                <div class='col-xs-2'>
+					<?php echo form_checkbox(array(
+						'name' => 'migrate_sales_history',
+						'id' => 'migrate_sales_history',
+						'value' => 'migrate_sales_history',
+						'checked'=>$this->config->item('migrate_sales_history'))); ?>
+                </div>
+            </div>
+
+            <div class="form-group form-group-sm">
+				<?php echo form_label($this->lang->line('config_migrate_sales_history_block'), 'migrate_sales_history_block', array('class' => 'control-label col-xs-2')); ?>
+                <div class='col-xs-2'>
+					<?php echo form_input(array(
+						'name' => 'migrate_sales_history_block',
+						'id' => 'migrate_sales_history_block',
+						'class' => 'form-control input-sm required',
+						'type' => 'number',
+						'value'=>$this->config->item('migrate_sales_history_block'))); ?>
+                </div>
+            </div>
+
+            <div class="form-group form-group-sm">
 				<?php echo form_label($this->lang->line('config_default_sales_discount'), 'default_sales_discount', array('class' => 'control-label col-xs-2 required')); ?>
 				<div class='col-xs-2'>
 					<div class="input-group">
diff --git a/database/3.0.2_to_3.1.0.sql b/database/3.0.2_to_3.1.0.sql
index d9d6cebfa..4cdee1979 100644
--- a/database/3.0.2_to_3.1.0.sql
+++ b/database/3.0.2_to_3.1.0.sql
@@ -228,3 +228,8 @@ INSERT INTO `ospos_app_config` (`key`, `value`) VALUES ('giftcard_number', 'seri
 -- add option to print company name in receipt
 
 INSERT INTO `ospos_app_config` (`key`, `value`) VALUES ('receipt_show_company_name', '1');
+
+-- add options to support sales tax history migration
+
+INSERT INTO `ospos_app_config` (`key`, `value`) VALUES ('migrate_sales_history', '0');
+INSERT INTO `ospos_app_config` (`key`, `value`) VALUES ('migrate_sales_history_block', '0');
diff --git a/database/database.sql b/database/database.sql
index 116f52a1b..2e50e49d2 100644
--- a/database/database.sql
+++ b/database/database.sql
@@ -96,7 +96,9 @@ INSERT INTO `ospos_app_config` (`key`, `value`) VALUES
 ('default_origin_tax_code', ''),
 ('cash_decimals', '2'),
 ('financial_year', '1'),
-('giftcard_number', 'series');
+('giftcard_number', 'series'),
+('migrate_sales_history', '0'),
+('migrate_sales_history_block', '0');
 
 
 -- --------------------------------------------------------
diff --git a/database/tables.sql b/database/tables.sql
index 43fecdf00..69c1ede31 100644
--- a/database/tables.sql
+++ b/database/tables.sql
@@ -96,7 +96,10 @@ INSERT INTO `ospos_app_config` (`key`, `value`) VALUES
 ('default_origin_tax_code', ''),
 ('cash_decimals', '2'),
 ('financial_year', '1'),
-('giftcard_number', 'series');
+('giftcard_number', 'series'),
+('migrate_sales_history', '0'),
+('migrate_sales_history_block', '0');
+
 
 
 -- --------------------------------------------------------