PHP List 2.10.4
There is a bug in PHP List 2.10.4 where if you try to send HTML Emails to your users and you did not import them with the "I prefer to receive emails in HTML format" Checked then no matter what you do they will get the Emails in plain text. You have to make sure that you import names with "I prefer to receive emails in HTML format" Checked.
A new release of phpList is available - 3.0.9
In phpList 3.0.9, users will:
No longer be able to inadvertently upload a binary file, such as an exel file which would create garbled data in a subscriber list
Be able to see a list of all subscribers, including those not on a list, to make it clearer how many subscribers are in the system in total. This is automatic in hosted, configurable in download.
Be able to remove all un-validated emails with one click. Ref. Source 2
PHPList just came out with another update: 3.0.10 which fixes two issues:
They've released what is supposed to be a newer version of phpList listed as version 3.3.0. Since phpList 3.3.0 works on bugs and security fixes you should update your version as soon as possible.