Just run this apt install command
sudo apt install pepperflashplugin-nonfree browser-plugin-freshplayer-pepperflash
After this restart your browser and check Adobe's site to verify if your Pepper flash is working and showing at least version 32.
https://helpx.adobe.com/flash-player.html
As you'll see below it will download the latest version which is currently 32 and this was not possible with the old/crappy deprecated adobe-flash plugin.
sudo apt install pepperflashplugin-nonfree
Reading package lists... Done
Building dependency tree
Reading state information... Done
Suggested packages:
chromium-browser ttf-mscorefonts-installer ttf-dejavu ttf-xfree86-nonfree
The following NEW packages will be installed:
pepperflashplugin-nonfree
0 upgraded, 1 newly installed, 0 to remove and 310 not upgraded.
Need to get 5,620 B of archives.
After this operation, 30.7 kB of additional disk space will be used.
Get:1 http://archive.ubuntu.com/ubuntu xenial-updates/multiverse amd64 pepperflashplugin-nonfree amd64 1.8.2ubuntu1.1 [5,620 B]
Fetched 5,620 B in 0s (15.1 kB/s)
Selecting previously unselected package pepperflashplugin-nonfree.
(Reading database ... 323899 files and directories currently installed.)
Preparing to unpack .../pepperflashplugin-nonfree_1.8.2ubuntu1.1_amd64.deb ...
Unpacking pepperflashplugin-nonfree (1.8.2ubuntu1.1) ...
Setting up pepperflashplugin-nonfree (1.8.2ubuntu1.1) ...
--2020-05-07 13:02:47-- https://fpdownload.adobe.com/pub/flashplayer/pdc/32.0.0.363/flash_player_ppapi_linux.x86_64.tar.gz
Resolving fpdownload.adobe.com (fpdownload.adobe.com)... 2.22.72.174, 2001:569:139:193::11e2, 2001:569:139:198::11e2
Connecting to fpdownload.adobe.com (fpdownload.adobe.com)|2.22.72.174|:443... connected.
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