Pegasus Mail has three renderers, TER, BearHTML and IERenderer. Normally, IERenderer is enabled by default. When disabled, BearHTML takes over. TER steps up when BearHTML is disabled which is an intentional act not easily done. IERenderer is updated regularly so that is the one to use. It has its own toolbar button. It is the rightmost one that looks like the Internet Explorer logo "e" superimposed with the Pegasus flying horse. Hovering over it with your cursor will reveal the installed version. Clicking it brings up its menu. Look at the "Use IERenderer" item. A checkmark indicates that it is enabled. No checkmark means it is disabled. While there, notice the "Auto Update Check". When enabled, Pegasus Mail will check for a new version of IERenderer each time it starts up. A red exclamation point will be added to the toolbar icon when a new version is available. It will not be installed automatically. You will need to download and install it.
Finally, the IERenderer menu contains an item called "Configure IERenderer". This is where you can look at the options available. I suggest sticking with the defaults but there is extensive help info available. Click the box containing the question mark for details. The "Configure IERenderer" item is greyed out when a text-only message has focus. Clicking on a message containing HTML will make it available.
Below is the URL to the IERenderer history page. It contains links to the download of each version.
https://www.pmpgp.de/renderer/History.htm
Pegasus Mail has three renderers, TER, BearHTML and IERenderer. Normally, IERenderer is enabled by default. When disabled, BearHTML takes over. TER steps up when BearHTML is disabled which is an intentional act not easily done. IERenderer is updated regularly so that is the one to use. It has its own toolbar button. It is the rightmost one that looks like the Internet Explorer logo "e" superimposed with the Pegasus flying horse. Hovering over it with your cursor will reveal the installed version. Clicking it brings up its menu. Look at the "Use IERenderer" item. A checkmark indicates that it is enabled. No checkmark means it is disabled. While there, notice the "Auto Update Check". When enabled, Pegasus Mail will check for a new version of IERenderer each time it starts up. A red exclamation point will be added to the toolbar icon when a new version is available. It will not be installed automatically. You will need to download and install it.
Finally, the IERenderer menu contains an item called "Configure IERenderer". This is where you can look at the options available. I suggest sticking with the defaults but there is extensive help info available. Click the box containing the question mark for details. The "Configure IERenderer" item is greyed out when a text-only message has focus. Clicking on a message containing HTML will make it available.
Below is the URL to the IERenderer history page. It contains links to the download of each version.
https://www.pmpgp.de/renderer/History.htm