Using a search engine, identify three desktop mail clients and two Android mail clients that support Web Key Directory (WKD). For each, specify the version from which WKD support is available if mentioned. Additionally, list two mail service providers that offer WKD support and their implementation dates.
Navigate to a search engine (e.g., DuckDuckGo). Search for 'WKD supported mail clients and service providers'. Review the search results to identify three desktop mail clients with WKD support and their versions. Review the search results to identify two Android mail clients with WKD support and their versions. Review the search results to identify two mail service providers with WKD support and their implementation dates. Compile all identified information into a concise answer.
List three desktop mail clients with WKD support and their respective versions (if specified). Acceptable clients include: Thunderbird/Enigmail 2.0, KMail 5.6, Outlook with GpgOL 2.2.0 or 3.1.10, Claws Mail 3.18.0 / 4.0.0, Balsa (merged). List two Android mail clients with WKD support and their respective versions (if specified). Acceptable clients include: K9Mail with OpenKeyChain 5.1, FairEmail with OpenKeyChain 5.4. List two mail service providers with WKD support and their implementation dates. Acceptable providers include: Forward Email (Since 2023-12-27), Posteo (Since 2016-12), Protonmail (Since 2018-11), netzguerilla (Since 2017-10-11), systemli.org (Since 2020-10-15), mailbox.org (claims, 2019 announcement), mail.de, Mailfence (Since 2021-11-18). All information must be extracted from the search results or directly linked pages, not inferred from prior knowledge.