Update and Activation Hook plugin.

How to check the Wordpress plugin activate and update

The below code is plugin codes used for adding new functionality setup 
while updating the plugin or activating the plugin.

This is simple plugin code and it will add transient while updating or activating the plugin.
Clear transient once we finished the operation.

=======================================================================================

<?php
/*Plugin Name: Wordpress Update
Plugin URI: https://test/wordpress-plugin-update-hook-upgrader_process_complete/
Description: Just an example of using upgrader_process_complete
Version: 1.0.0
Author: Test Theme
Author URI: https://test.com/
Text Domain: wordpress-update
Domain Path: /languages*/

// Exit if accessed directly
if ( ! defined( 'ABSPATH' ) ) {
 exit;
}

/**
 * This function runs when WordPress completes its upgrade process
 * It iterates through each plugin updated to see if ours is included
 * @param $upgrader_object Array
 * @param $options Array
 */
function wp_upe_upgrade_completed( $upgrader_object, $options ) {
 // The path to our plugin's main file
 $our_plugin = plugin_basename( __FILE__ );
 // If an update has taken place and the updated type is plugins and the plugins element exists
 if( $options['action'] == 'update' && $options['type'] == 'plugin' && isset( $options['plugins'] ) ) {
  // Iterate through the plugins being updated and check if ours is there
  foreach( $options['plugins'] as $plugin ) {
   if( $plugin == $our_plugin ) {
    // Set a transient to record that our plugin has just been updated
    set_transient( 'wp_upe_updated', 1 );
   }
  }
 }
}
add_action( 'upgrader_process_complete', 'wp_upe_upgrade_completed', 10, 2 );

/**
 * Show a notice to anyone who has just updated this plugin
 * This notice shouldn't display to anyone who has just installed the plugin for the first time
 */
function wp_upe_display_update_notice() {
 // Check the transient to see if we've just updated the plugin
 if( get_transient( 'wp_upe_updated' ) ) {
  echo '<div class="notice notice-success">' . __( 'Thanks for updating', 'wp-upe' ) . '</div>';
  delete_transient( 'wp_upe_updated' );
 }
}
add_action( 'admin_notices', 'wp_upe_display_update_notice' );

/**
 * Show a notice to anyone who has just installed the plugin for the first time
 * This notice shouldn't display to anyone who has just updated this plugin
 */
function wp_upe_display_install_notice() {
 // Check the transient to see if we've just activated the plugin
 if( get_transient( 'wp_upe_activated' ) ) {
  echo '<div class="notice notice-success">' . __( 'Thanks for installing', 'wp-upe' ) . '</div>';
  // Delete the transient so we don't keep displaying the activation message
 delete_transient( 'wp_upe_activated' );
 }
}
add_action( 'admin_notices', 'wp_upe_display_install_notice' );

/**
 * Run this on activation
 * Set a transient so that we know we've just activated the plugin
 */
function wp_upe_activate() {
 set_transient( 'wp_upe_activated', 1 );
}
register_activation_hook( __FILE__, 'wp_upe_activate' );




Reference:   https://pluginrepublic.com/wordpress-plugin-update-hook-upgrader_process_complete/