# How to upgrade a Thunderbird 20-58 Addon that uses XUL?

**URL:** <https://discourse.mozilla.org/t/how-to-upgrade-a-thunderbird-20-58-addon-that-uses-xul/51360>\
**Category:** Add-ons\
**Created:** [January 3, 2020, 2:10pm UTC](https://discourse.mozilla.org/t/how-to-upgrade-a-thunderbird-20-58-addon-that-uses-xul/51360 "2020-01-03T14:10:04Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![MMarkus](https://avatars.discourse-cdn.com/v4/letter/m/e47c2d/32.png) [@MMarkus](https://discourse.mozilla.org/u/MMarkus)\
**Post date:** [January 3, 2020, 2:10pm UTC](https://discourse.mozilla.org/t/how-to-upgrade-a-thunderbird-20-58-addon-that-uses-xul/51360/1 "2020-01-03T14:10:04Z")

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Hi  
I would like to update my addon [https://addons.thunderbird.net/de/thunderbird/addon/addresslabel](https://addons.thunderbird.net/de/thunderbird/addon/addresslabel)  
that uses XUL.

Where do I start?

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**Author:** ![DaveRo](https://avatars.discourse-cdn.com/v4/letter/d/838e76/32.png) [@DaveRo](https://discourse.mozilla.org/u/DaveRo)\
**Post date:** [January 3, 2020, 10:55pm UTC](https://discourse.mozilla.org/t/how-to-upgrade-a-thunderbird-20-58-addon-that-uses-xul/51360/2 "2020-01-03T22:55:52Z")

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Firstly, there were some changes required for TB 60. Take a look here: [https://wiki.mozilla.org/Thunderbird/Add-ons\_Guide\_57](https://wiki.mozilla.org/Thunderbird/Add-ons_Guide_57)

Then there were more significant changes required for TB68: [https://developer.thunderbird.net/add-ons/tb68](https://developer.thunderbird.net/add-ons/tb68)

And the best forum for addon development is now here: [https://thunderbird.topicbox.com/groups/addons](https://thunderbird.topicbox.com/groups/addons)

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**Author:** ![C-E](https://avatars.discourse-cdn.com/v4/letter/c/bc8723/32.png) [@C-E](https://discourse.mozilla.org/u/C-E)\
**Post date:** [January 4, 2020, 10:44pm UTC](https://discourse.mozilla.org/t/how-to-upgrade-a-thunderbird-20-58-addon-that-uses-xul/51360/3 "2020-01-04T22:44:31Z")

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Markus, you should also read this:

> **[Update for Thunderbird 78 | Thunderbird](https://developer.thunderbird.net/add-ons/tb78)**
>
> Required steps to update add-ons for Thunderbird 78.

That means, if you want that your addon will keep working after the next major update, you should convert it to a “MailExtension” or a “Web Extension Experiment”.  
Most probably the API’s needed for a “MailExtension” are not yet available, so most probably the way to go is to convert your addon to a “Web Extension Experiment”.

If you like, you can use my example “Search Button Addon” as a starting point and put in your code:

> **[GitHub - c-e-github/Thunderbird-Addon-SearchButton: Extension that implements a button, which when...](https://github.com/c-e-github/Thunderbird-Addon-SearchButton)**
>
> Extension that implements a button, which when clicked, invokes the message search window.