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.
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
chromium-browser ttf-mscorefonts-installer ttf-dejavu ttf-xfree86-nonfree
The following NEW packages will be installed:
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/18.104.22.1683/flash_player_ppapi_linux.x86_64.tar.gz
Resolving fpdownload.adobe.com (fpdownload.adobe.com)... 22.214.171.124, 2001:569:139:193::11e2, 2001:569:139:198::11e2
Connecting to fpdownload.adobe.com (fpdownload.adobe.com)|126.96.36.199|:443... connected.
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