Send Later Version History

84 versions

Be careful with old versions!

These versions are displayed for reference and testing purposes. You should always use the latest version of an add-on.

Version 6.2.1 335.8 KiB Works with SeaMonkey 2.9 - 2.54, Thunderbird 8.0a1 - 57.0

Add a new preference controlling whether scheduled drafts are marked as read in the drafts folder or remain marked unread. This preference is enabled by default, i.e., drafts are marked read by default, because I believe this is the behavior the majority of users want.

Update translations, including the start of a new (not yet complete) Czech translation.

Version 6.2 322.4 KiB Works with SeaMonkey 2.9 - 2.53, Thunderbird 8.0a1 - 56.0

New feature: Automatically cancelling recurring messages upon reply

When scheduling a recurring message via the Send Later pop-up window, you may now indicate that the recurring message should be canceled and deleted from your Drafts folder if you receive a reply to it. This is useful, e.g., if you want to keep periodically reminding someone about something until they reply to indicate that the reminder is no longer needed.

Thanks, as always, to my translation volunteers, for assisting in translating this new feature to many languages!

New feature: Draft messages saved by Send Later are now more reliably marked as “read” so they don’t make your Drafts folder have an unread count unnecessarily.

Bug fixes:

Send Later now uses separate, unique message IDs for scheduled drafts vs. the messages it actually sends, as well as for different copies of recurring messages. Previously, the message ID which Send Later used when sending a scheduled message was identical to the message ID that was used while the message was being stored in your Drafts folder. Furthermore, Send Later previously used that same message ID for all sent copies of recurring messages. Using the same message ID for drafts and recurring messages was incorrect both because message IDs of different copies of messages are supposed to be unique, and because some mail servers might get confused when a draft and a sent message have the same message ID.

Previously, when a recurring message was sent, Send Later briefly failed to include it in the count of pending messages. Now, Send Later consistently counts recurring messages in the pending message count.

Version 6.1.3 316.4 KiB Works with SeaMonkey 2.9 - 2.53, Thunderbird 8.0a1 - 56.0

New Russian translation.

Minor updates to some other translations.

Version 6.1.2 304.9 KiB Works with SeaMonkey 2.9 - 2.53, Thunderbird 8.0a1 - 56.0

Guard against a corrupted Outbox causing messages to be resent

Thunderbird’s local folder storage format keeps deleted messages on disk, but invisible to the user, until their folder is compacted. Usually this causes no trouble, but occasionally Thunderbird corrupts a local folder and loses track of messages which messages were deleted, causing them to “magically” appear in the folder again. In most cases, this causes no further harm than deleted messages being resurrected, an annoying nuisance but not a huge problem.

However, when Send Later is being used, and when the folder this happens to is the user’s Outbox folder, it can cause a big problem: messages that were previously sent with Send Later can be resurrected and resent. If it has been a long time since the Outbox was last compacted, a lot of messages can be resent. This is bad.

Send Later now guards against this by by automatically compacting the Outbox folder whenever Thunderbird finishes sending its messages and it is visibly empty, i.e., the only messages remaining in it are invisible, deleted messages.

Make locale-based first-day-of-week work in calendar pop-ups

There is a bug in Thunderbird which was preventing the calendar pop-ups displayed by Send Later from starting the week on the correct day, in locales where that day isn’t Sunday. See Fortunately, there’s a workaround for this bug, which has now been implemented in Send Later. Therefore, if your computer starts weeks with the correct day elsewhere, it should now do so in the Send Later calendar pop-ups as well.

Miscellaneous minor changes

The command key for the “Close” button in the dynamic function editor is now Ctrl-W in every language, as it should be.

A bunch of button access keys (i.e., the letters you an type with Alt to activate the buttons) have been fixed.

Use the Unicode ellipsis character instead of three periods. Also, use Unicode quotes instead of ASCII double quotes.

Be more consistent about the add-on name in translations, i.e., decide for each translation whether the add-on name is going to be “Send Later” in English or a translated version, and carry that decision throughout the entire translation.

Translation updates.

Update the URL of the user guide because it’s got SSL (https) now.

Version 6.1 299.2 KiB Works with SeaMonkey 2.9 - 2.51, Thunderbird 8.0a1 - 54.0

Enhancements to day/time restrictions and scheduling functions

Previously, the day-of-week and time-of-day restrictions in the Send Later prompt window could only be used with recurring messages or scheduling functions. Now they can be used when specifying only a single send time explicitly as well. You can do some clever things when combining this with saving defaults in the prompt window. For example, if you always want messages to be sent within a particular time window, you could put "now" in the prompt window's text box and specify the desired time window in the "Between" settings, then save those defaults, and from then on, whenever you bring up the prompt window and click the "Send at" button, it'll either send the message immediately -- if it's within the correct time window -- or move it to be within the time window.

Previously, when you used a non-recurring dynamic scheduling function such as the "BusinessHours" function that is created by default when you open the dynamic function editor, the fact that the message was scheduled with a function is not saved, so if you go to edit the function later and then try to re-schedule it, rather than defaulting to using the same dynamic function again, it defaulted to the time that the message was previously scheduled to be sent. Now, the function name is saved, and if you edit and re-schedule the message the prompt window will be pre-configured to use it again.

Furthermore, when you specify day-of-week or time-of-day restrictions when scheduling a message with either an explicit send time or a non-recurring dynamic function, the restrictions you specify will now be saved, so that if you edit and re-schedule the message, they will be set up in the prompt window automatically.

Other enhancements

When you click the "Calculate" button in the prompt window, the text-box the date and time pickers are now updated with the results along with the text box.

If you accidentally click "Save defaults" or "Clear defaults" in the prompt window, you can now click it again to undo the first click (prevously, once you clicked either of them, you then had to leave one or the other selected).

In Postbox, the Send Later status message and progress bar in the main window has been moved to the system tray, which is deprecated in Postbox, to below the folder list.

The Catalan, Dutch, and German translations have been updated.

Bug fixes

A bug which prevented a scheduled message with a day-of-week restriction from being sent unless it also had a time-of-day restriction has been fixed.

Automatically displaying the release notes for new major or minor releases was broken in release 6.0 and is now fixed.

The logic for displaying the release notes for new major or minor releases had a bug which was causing it to sometimes display them for patch releases as well. This has been fixed, and now the release notes will be displayed only for major, minor, and beta releases (the latter obviously only for users who are subscribed to the beta release channel).

Send Later's translations use parameterized substitutions in some translated strings, i.e., the string is used as a template into which values are substituted to customize it for the particular message being displayed. A few of the rarely used strings had missing or incorrect substitution patterns in them in some languages. In addition to fixing these, the build process for the add-on has been modified to prevent similar bugs from being introduced in the future.

Non-functional changes

Fix an undefined variable reference in some code that should never actually be executed since it indicates an internal error in the add-on.

Fix some incorrect invocations of Array.splice which were treating the second argument as the end index of the splice, rather than as the number of elemented to replace in the array. These incorrect invocations weren't actually having a functional impact because of the way the code was otherwise constructed, but they could at some point in the future and they were clearly wrong, so they've been fixed.

The code that was supposed to display an error pop-up when there was an unexpected error invoking a dynamic scheduling function was broken, and that code would itself cause an uncaught error and cause the add-on to malfunction. Users are unlikely to have run into this issue, but in any case it has been fixed.

Version 6.0.3 296.3 KiB Works with SeaMonkey 2.9 - 2.48, Thunderbird 8.0a1 - 51.0

BUG: Scheduling messages with monthly recurrence was broken and has been fixed.

BUG: Fix incompatibility with Thunderbird versions before 17.

BUG: Fix incompatibility with Seamonkey versions newer than 2.41a1.

BUG: Fix the pop-up menu in the main Thunderbird window so it only pops up when you click on the Thunderbird part of the status bar, rather than when you click anywhere in the status bar.

ENHANCEMENT: When there are no dynamic scheduling functions defined, i.e., before the first time the user has opened the dynamic function editor, desensitize the dynamic function selector in the Send Later prompt window, since there are no dynamic functions to select.

ENHANCEMENT: Fix the height of the dynamic function pop-up menu in theSend Later prompt window so that it is correctly full height, rather than being very short until the user selects a function.

I18N: Translation updates.

Version 6.0.2 273.7 KiB Works with SeaMonkey 2.9 - 2.40.*, Thunderbird 8.0a1 - 51.0

This release of Send Later includes several exciting new features!

Dynamic scheduling function support

Send Later 6.0 includes a totally new dynamic scheduling function editor and makes dynamic scheduling functions fully accessible through the Send Later dialog and shortcut buttons. This means that you can easily write JavaScript function to implement arbitrarily complex message scheduling logic (for example, the most common request I get: "Can I click a button to make the message send during business hours, rather than in the middle of the night when I'm composing it?").

Read more in the updated user guide or click on “Send Later” in your status bar and select “Dynamic function editor” to open the editor and read the built-in documentation.

While it was possible to use dynamic scheduling functions in previous Send Later releases, it required significant "back-end" configuration and a reliance on other add-ons; this is no longer the case.

Save default settings in the Send Later dialog

You can now save default settings in the Send Later dialog when scheduling a message, and subsequent invocations of the dialog (until you clear the defaults) will start with the settings you saved.

Pop-up menu on main Thunderbird window

There is now a pop-up menu accessible by clicking on “Send Later” in the status bar, giving you easy access to Send Later’s preferences, dynamic function editor, user guide, release notes, emailing the author, and making a donation.

SpamFighter compatibility

Send Later is now compatible with SpamFighter.

Improved Send Later icons

The Send Later icons have been improved a bit.


This release includes a new Catalan translation, and an incomplete Greek translation.

This release also includes various other translation updates. Thanks, as always, to my translators, in particular my new Polish translator, Piotr Przybylski (Gabry$).

Bug fixes

A bug in the interpretation of day-of-week restrictions, which could sometimes cause recurring messages subject to such restrictions to be sent on the wrong day, has been fixed.

Version 5.2.1 189.3 KiB Works with SeaMonkey 2.9 - 2.40.*, Thunderbird 8.0a1 - 51.0

Summary: If you need the "Put in Outbox" button in the Send Later dialog, then you need to launch the dialog using Ctrl-Shift-Enter, the "File | Send Later" menu command, or the button provided by the "Send Later Button" add-on. If, on the other hand, you need the "Send Now" button in the Send Later dialog, then you need to have the "'Send' does 'Send Later'" preference enabled, and you need to launch the dialog using the "Send" button, Ctrl-Enter, or the "File | Send Now" menu command. Please read on for the details surrounding this change.

There has been a lot of flip-flopping in this area of the add-on's functionality, caused in part by the fact that there are so many moving parts that I've had trouble keeping them all straight in my mind, so I'm going to try to explain clearly here exactly what's going on and why I'm reverting this change, so that all the necessary information is known going forward.

There are two buttons in the Send Later prompt window: "Put in Outbox" and "Send Now". These two buttons bypass the Send Later message scheduling mechanism in two different ways:

  • "Put in Outbox" puts the message being edited directly into the Thunderbird Outbox folder, such that it will be delivered the next time the user (or Send Later, or BlunderDelay) executes the "File | Send Unsent Messages" menu command.
  • "Send Now" delivers the message to its intended recipients immediately rather than scheduling the message for later delivery with Send Later.

Unfortunately, the only way that both of these buttons can always work is if Send Later "cheats" and does things it's not supposed to during the message scheduling and delivery process. This cheating causes all sorts of other issues, such as incompatibilities with other add-ons, Thunderbird popping up warnings and spell-checking windows multiple times, etc., so it's a rather bad idea, and we don't want Send Later to be doing that.

Therefore, in a recent release of Send Later, the cheating was removed, and that meant it was no longer possible for both of these buttons to work properly every time the Send Later dialog is displayed. In particular:

  • If the Send Later dialog is opened with Thunderbird's own Send Later command, i.e., typing Ctrl-Shift Enter, selecting the "File | Send Later" menu command, or using the button provided by the "Send Later Button" add-on, then it is possible to make the "Put in Outbox" button work properly in the dialog, but it is not possible to make the "Send Later" button work.
  • Conversely, if the user has the "'Send' does 'Send Later'" preference enabled, such that Thunderbird's own "Send Now" command (i.e., typing Ctrl-Enter, selecting the "File | Send Now" menu command, or clicking the "Send" button) is used to launch the Send Later dialog, then in that particular instance of the dialog, it is possible to make the "Send Now" button work properly, but it is not possible to make the "Put in Outbox" button work.

Because the removal of the cheating code meant it was no longer possible to make both of these buttons work every time the dialog was opened, Send Later's code was modified to display only the button that will actually work properly.

After the release with this change was shipped, I started to get feedback from users complaining -- in some cases rather vociferously -- about this change. Some people complained about the disappearance of the "Send Now" button, others complained about the missing "Put in Outbox" button.

At this point, I should have explained as above why it was no longer possible for both of these buttons to be present, and further explained that if the user needs the "Send Now" button, the dialog needs to be launched with the "Send" button or Ctrl-Enter or "File | Send Now", whereas if the "Put in Outbox" button is needed, the dialog needs to be launched with the "Send Later" button or Ctrl-Shift-Enter or "File | Send Later".

Unfortunately, with all of the complaints coming in, I got confused, and I somehow convinced myself that the buttons were removed not because it was not possible to make them work all the time without cheating, but rather because users were sometimes getting confused and clicking one of these buttons when it wasn't actually needed. Actually, reducing the likelihood of user confusion wasn't the reason why the buttons were removed; it was merely a beneficial side-effect.

I need to apologize to those users whom I told that the buttons were removed to reduce user confusion. I was wrong. I'm sorry for giving you incorrect information.

I also need to apologize to everyone for the "churn" of putting out release 5.2 which added a preference which puts both buttons back, when in fact with that preference enabled, one of the buttons in the dialog is always going to function incorrectly. So rather than solving the problem I hoped to solve in release 5.2, I introduced a new problem, an actual bug, which could cause messages to be put into the user's Outbox when the user intended to send them, or sent directly when the user intended to put them in the Outbox. I'm sorry.

Release 5.2, which introduced potentially incorrect behavior as described above, has been removed from and is no longer available for downloads or automatic upgrades.

This new release undoes the change introduced in release 5.2. There is no longer a preference to cause both of the buttons to be displayed all the time, because it is simply not possible to make that work properly without Send Later interacting with Thunderbird in a way that it's not supposed to and that isn't sustainable or maintainable.

Just to reiterate, if you need the "Put in Outbox" button in the Send Later dialog, then you need to launch the dialog using Ctrl-Shift-Enter, the "File | Send Later" menu command, or the button provided by the "Send Later Button" add-on. If, on the other hand, you need the "Send Now" button in the Send Later dialog, then you need to have the "'Send' does 'Send Later'" preference enabled, and you need to launch the dialog using the "Send" button, Ctrl-Enter, or the "File | Send Now" menu command.

If you don't have the "'Send' does 'Send Later'" preference enabled, and you launch the Send Later dialog the normal way (with Ctrl-Shift-Enter, "File | Send Later", or the "Send Later Button" button), and then you decide that actually you want to send the message right away, all you need to do is close the Send Later dialog or click the Cancel button and then send the message normally.

I am sorry to those of you whose workflows are disrupted by this change. If you are unable to figure out a new workflow which accommodates this change, please email me and describe to me in detail how you're using the add-on and how this change is impacting you, and I will try to help you find a way to make it work.

Version 5.1 189.5 KiB Works with SeaMonkey 2.9 - 2.40.*, Thunderbird 8.0a1 - 51.0

Send Later is now fully compatible with Enigmail! Many thanks to Patrick Brunschwig from the Enigmail development team for working with me to make this possible.

Thunderbird now pops up the spell-check-before-send window (if it is enabled) and checks messages for empty Subject lines when they are scheduled using buttons or input fields on the compose window toolbar. Previously, neither spell-checking nor the empty-subject check would happen in this context (i.e., this was a bug, and it is now fixed).

The "Send Now" button in the Send Later dialog now pops up a dialog when it is used, to ensure that users don't click it when they actually meant to click the scheduled send button. There is a checkbox in this dialog to allow it to be suppressed in the future.

In a further effort to reduce confusion about the "Put In Outbox" and "Send Now" buttons in the Send Later dialog, the "Put In Outbox" button is now only visible when the dialog is popped up using "File | Send Later" or Ctrl-Shift-Enter, and the "Send Now" button is now only visible when the "'Send' Does 'Send Later'" preference is enabled and the dialog is popped up using "File | Send Now" or Ctrl-Enter.

This release includes many translation updates. Thanks, as always, to my wonderful team of translators!

This release increases compatibility settings for newer Thunderbird and Seamonkey releases.

As a side benefit of the other work enumerated above, a good chunk of the add-on's code has been cleaned up and refactored.

Version 5.0.1 169.1 KiB Works with SeaMonkey 2.9 - 2.40.*, Thunderbird 8.0a1 - 50.0

Fixed a couple of bugs in the time-of-day restriction functionality introduced in release 5.0.

Version 5.0 169.1 KiB Works with SeaMonkey 2.9 - 2.40.*, Thunderbird 8.0a1 - 50.0

There are some exciting changes in this release of Send Later!

New features:

  • Messages can now be scheduled to send on a minutely basis, i.e., every minute, or every 2 minutes, or every 3 minutes, etc.
  • Delivery of recurring messages can now be restricted by time of day and day of week. This restriction is enforced on the message's initial scheduled delivery time and in each subsequently scheduled recurring delivery. Furthermore, there is a preference you can enable to enforce it on late message delivery as well. In other words, if Thunderbird isn't running when at the scheduled delivery time, and when you launch Thunderbird the current time conflicts with the delivery restrictions, then by default the message will be delivered despite the conflict, but if you enable the preference, then delivery will be delayed until the delivery restrictions are satisfied.
  • There is a new preference you can enable to prevent Send Later from delivering messages late, e.g., because Thunderbird wasn't running at the scheduled delivery time. When this preference is enabled, Send Later will pop up a warning about the late message instead of delivering it.

Bug fixes:

  • The shortcut buttons in the compose window toolbar are now disabled when a previously scheduled message with recurrence is edited. In this context, the user should open the Send Later dialog to reschedule the message, rather than using shortcut buttons.
  • The "week of the month" checkbox (e.g., "1st Saturday of the month", "3rd Tuesday of the month") in the scheduling dialog is now disabled correctly when the user clears the scheduled send time or switches to a recurrence frequency other than monthly.

Version 4.4.5 152.7 KiB Works with SeaMonkey 2.9 - 2.40.*, Thunderbird 8.0a1 - 49.0

Disable scheduling messages when Enigmail is active

Unfortunately, limitations in the Thunderbird add-on framework make it somewhere between difficult and impossible to make scheduled messages with Send Later work safely and properly when the Enigmail add-on is installed and enabled.

However, Send Mail can successfully deliver previously scheduled messages even when Enigmail is active.

Therefore, Send Later now displays an alert pop-up and disables the scheduling of messages when Enigmail is enabled. If/when Enigmail is disabled or uninstalled and Thunderbird is restarted, Send Later automatically re-enables itself.

Version 4.4.4 150.5 KiB Works with SeaMonkey 2.9 - 2.40.*, Thunderbird 8.0a1 - 46.0

Bug: Fix Send Later column after using quick filter

Previously, if you used the quick filter bar to search messages in the Drafts folder, then the Send Later column would stop working. This is fixed.

Bug: Fix incompatibility with the Mnenhy add-on

Recent necessary changes made Send Later incompatible with the Mnenhy add-on, because Mnenhy replaces certain core Thunderbird components. Send Later now has a workaround for this problem.

Version 4.4.3 150.2 KiB Works with SeaMonkey 2.9 - 2.39, Thunderbird 8.0a1 - 43.0

Bug fix: If the user runs Thunderbird when the system clock is incorrectly set in the future, and then subsequently the system clock is fixed, Send Later would stop delivering scheduled messages.

Bug fix: Don’t display the “Every” checkbox in the Send Later prompt window when it’s not relevant.

Bug fix: Before this fix, Send Later was sometimes causing displayed message headers to be aligned incorrectly.

Bug fix: Replace a reference to “Send Later 3″ in the user interface with “Send Later”.

New Brazilian Portuguese translation, thanks to wetabax from BabelZilla.

Non-functional (invisible to users) changes to make the add-on validator happy.

Upgrade SugarJS date-parsing library; this change should be invisible to users.

Version 4.4.1 151.2 KiB Works with SeaMonkey 2.9 - 2.37, Thunderbird 8.0a1 - 40.0

Compatibility fix for Thunderbird 37+.

Version 4.4 151.0 KiB Works with SeaMonkey 2.9 - 2.36, Thunderbird 8.0a1 - 36.*

All the shortcut keys in the Send Later prompt window mentioned in the user guide now work in Mac OS, using the Mac OS command key as for other standard Mac OS shortcut keys.

On other platforms (e.g., Windows, Linux), the key for activating shortcuts has changed from Alt to Ctrl.

The Ctrl key is what we should have been using all along, but we were using Alt instead for historical reasons. In order to make shortcuts work on Mac OS, we need to standardize on the "correct" shortcut key on all platforms, hence the change on the other platforms.

Version 4.3.1 151.0 KiB Works with SeaMonkey 2.9 - 2.36, Thunderbird 8.0a1 - 39.0

Fix the accelerator keys for the shortcut buttons, i.e., you can now type Alt-1, Alt-2, or Alt-3 in the Send Later dialog to activate the first, second, or third shortcut button. This has been broken for over two years, but no one reported the problem until recently!

Update the Japanese translation. Thanks, as always, to my awesome translators!

Eliminate some unnecessary error log messages showing up in the error console. If you never look in the Thunderbird error console, this has no impact on you. ;-)

Version 4.3 150.9 KiB Works with SeaMonkey 2.9 - 2.34, Thunderbird 8.0a1 - 37.0

Changes since release 4.2.4:
  • Send Later now warns you on exit if you have pending messages scheduled to be sent, to help you avoid accidentally quitting when you meant to leave the application running so it could send the messages. There is a checkbox in the message you can uncheck if you don't want to be warned again.
  • It is once again possible to use local mailing lists in scheduled messages. This functionality was broken by a recent Thunderbird release but is now fixed.
  • Translation updates. Thank you as always to my translators, including new translator Kari Eveli!
  • More robust performance in foreign languages.
Changes since release 4.2:
  • Scheduled messages are no longer sent repeatedly when the Drafts folder is corrupted. Instead, when Send Later encounters a message in the Drafts folder that it has already sent, it displays an error notifying the user that the Drafts folder needs to be repaired.
  • The X-Enigmail-Draft-Status header is now removed from scheduled messages before they are sent by Send Later.
  • Compatibility with Thunderbird 26+ and Seamonkey 2.23+.
  • Some debug log messages generated by Send Later have been downgraded in priority to make them easier for folks who care about such things to ignore them.

Version 4.2.4 147.5 KiB Works with SeaMonkey 2.9 - 2.32, Thunderbird 8.0a1 - 35.0

Remove the "X-Enigmail-Draft-Status" header before sending a scheduled message.

French and Dutch translation updates. Thanks, as always, to my translators!

Version 4.2.3 147.0 KiB Works with SeaMonkey 2.9 - 2.30, Thunderbird 8.0a1 - 33.0

Add a workaround for a Thunderbird / Postbox bug which occasionally causes Send Later to send messages multiple times.

Version 4.2.2 146.0 KiB Works with SeaMonkey 2.9 - 2.29, Thunderbird 8.0a1 - 32.0

Fix compatibility with old Thunderbird versions. Sorry about that!

Version 4.2.1 146.0 KiB Works with SeaMonkey 2.21a1 - 2.23a1, Thunderbird 24.0a1 - 26.0a1

Compatibility with Thunderbird 26+, SeaMonkey 2.23+.

Dutch and Finnish translation updates (thank you to my translators!). NOTE: I need a new translator for Traditional Chinese (zh-TW). If you're interested in helping out, please let me know (email! Thanks!

Fix home page URL.

Version 4.2.0 145.5 KiB Works with SeaMonkey 2.9 - 2.22, Thunderbird 8.0a1 - 25.0

Changes since 4.1.7:

When the user clicks on the "Put in Outbox" button, a warning now pops up explaining what that button does and why the user might actually want to click on the "Send around" button instead. There is a check-box in this pop-up to prevent it from being displayed in the future. The purpose of this new warning is to help alleviate the confusion from which some users suffer about which button to click to schedule a message.

New Armenian translation. Thanks to HrantOhanyan from BabelZilla!

Version 3.3.10 97.0 KiB Works with Thunderbird 2.0 - 14.*


The next version to be released after this one will include significant new functionality which cannot be implemented within Thunderbird 2 or Postbox 2. Users who do not wish to upgrade to a newer version of Thunderbird or Postbox may continue to use this version as-is, but there will be no further bug-fix or feature releases compatible with Thunderbird 2 or Postbox 2.