Can't get Newsletter Add-on working

[Allegro145]

Just installed this module but can't get it working.

Click Send Test Email button but never received actually received one;
Click Send Email button but none was sent out. All letter with 'Sending' status;
Click Save as New button, I have the following error:
PHP Deprecated: DataObject::set_validation_enabled is deprecated. Use the "DataObject.validation_enabled" config setting instead. Called from NewsletterGridFieldDetailForm_ItemRequest->doSaveAsNew. in /Applications/MAMP/htdocs/project/framework/dev/Deprecation.php on line 212

Can someone let me know how did you get this module work?
Many thanks.

[wilr]

@Allegro145 please provide your SilverStripe version number.

[Allegro145]

@wilr Thanks for replying. I have errors in SilverStripe 3.6.0 and 3.7.1

[Allegro145]

Hello there, Could someone please suggest which version of this Newsletter Add-on would work with SilverStripe 3.6.0, SilverStripe 3.7.1 or any other SilverStripe version? Or suggest how could I fix/avoid above errors?
I have installed dev-master (via Composer) version in both SilverStripe 3.6.0 and 3.7.1. I have errors in both tjese versions. Does this add-on has a stable version for SilverStripe 4.2.1?
Appreciate it very much if someone could please point me a right direction from here.

[Allegro145]

I guess following is where the code (deprecated) need to be changed but I am not too sure what/how it should be changed to? Newsletter::set_validation_enabled(false)

[dhensby]

@Allegro145 deprecation warnings are fine; just turn them off if they are being written to the screen and stopping you progressing.

[Allegro145]

@dhensby Thanks. It's a good way out even though I am not to sure how to turn the warnings off. I am finding difficult to follow/debug the newsletter modules/codes/programs...Finally managed gone pass the deprecated error (not by turning off warnings) and now struggling with the problems of it doesn't send out test emails and actual newsletters.... Any hints here??

[dhensby]

@Allegro145 afraid I can't be of much help as this it's been a very long time since I've used the module.

@wilr might know some more?