The security issue seems to be fixed as of KeePass 2.3.4 and it looks like the discussion about HTTPS and ads is missing the point.
From the website (http://keepass.info/help/kb/sec_issues.html#updsig
"There have been some articles about automatic KeePass updates being vulnerable. This section clarifies the situation and its resolution.
First of all, we would like to note that KeePass cannot update itself. KeePass does support checking for updates (optional; by downloading a version information file, comparing the available with the installed version number, and displaying a notification if necessary). However, it neither downloads nor installs any new version automatically. Users have to do this manually.
KeePass can be downloaded from many servers (SourceForge with its many mirror servers, FossHub, etc.). In order to make sure that the downloaded file is official, users should check whether the file is digitally signed (Authenticode; all KeePass binaries are signed, including the installer, KeePass.exe and all other EXE and DLL files). The digital signature can be checked using Windows Explorer by right-clicking the file -> 'Properties' -> tab 'Digital Signatures'. When running the installer, the UAC dialog displays the digital signature information, i.e. users who carefully read the UAC dialog do not have to inspect the file properties separately. This is recommended for all users, independent of where you download KeePass from.
The KeePass website links to SourceForge for downloading KeePass. However, even if SourceForge (or the KeePass website) is compromised and serves a malicious download, users who check the digital signature will notice the attack and will not run the malware. Note that HTTPS cannot prevent a compromise of the download server; checking the digital signature does.
The version information file is downloaded from the KeePass website over HTTP. Thus a man in the middle (someone who can intercept your connection to the KeePass website) could have returned an incorrect version information file, possibly making KeePass display a notification that a new KeePass version is available. However, the next steps (downloading and installing the new version) must be carried out by the user manually, and here users who check the digital signature will notice the attack.
Resolution. In order to prevent a man in the middle from making KeePass display incorrect version information (even though this does not imply a successful attack, see above), the version information file is now digitally signed (using RSA-2048 and SHA-512). KeePass 2.34 and higher only accept such a digitally signed version information file. This solution is more secure than just using HTTPS, because it guarantees version information safety even when the webserver is compromised (the private key for signing the version information is not stored on the webserver)."