How to manage communication during application downtime?

Here is what I do:

• State very clearly what the consequences are (right now and in the immediate future). Highlight likely permanent consequences or lack thereof (data loss, loss of employee-hours).
• Keep the tone very neutral. Do not spend energy on blame/guilt. Ideally this conveys "I want to give you information but my attention is also needed elsewhere".
• Your notification will be forwarded to a lot of people, make sure your CEO understands the gist within the first half paragraph. Usually I provide an 'executive summary'. Technical details can provide background information to other technical people.
• Provide contact details (preferably someone who has the time in the heat of the downtime) for further questions, and ask patience in the same sentence (this works often).
• Promise updates when the situation changes.

Send updates when there is good news, before office closing time ("all staff will continue through the night" - account for timezones if necessary) and again around office opening time.

When the issue is resolved (for any definition of that word), send:

• A summary including timing of the consequences
• The actions/changes taken on short term and planned for the future ("lessons learned"); based on:
• Technical root cause analysis

Keep any calls for blame, guilt or lynching in separate mails, preferably after some cooldown time.

Do not commit to anything during the downtime unless you are really, really sure you can deliver. Somehow two separate "bad news" situations are worse than a long one.

I prefer to use a medium where a notification is pushed on every message (mail, Twitter, ..)

The most important thing I've found both as a service provider and a service user is proactive responsibility. It's not able what you say, but when (how soon) you say it.

If you are notified that a problem happened and was fixed (or is being worked on), it's a lot better than discovering the problem yourself and trying to contact the vendor to figure out what in the world is going on. It also helps with the blame game and saves a lot of troubleshooting time (is it us or is it them?).

As far as detail goes, I find that giving a simple summary of what happened is nice unless users specifically request more information. There will be some people who always want as much detail as they can get, but most people just want things to work (even if they are highly technical).

Lastly, being able to explain what steps you have taken so that it won't happen again go a long way toward future goodwill and trust.

Without knowing much more about your particular app, how it's licensed, the field your providing services for, etc; it's impossible to answer your questions without guessing.

1. Owning up to your own mistakes is usually the route. Consult your lawyer if your field is one where many laws, SLAs, or meticulous contracts apply.
2. It's a fine line between too much and too little detail. In general enough detail that a common user would feel like they understand.
3. If it's a small and quickly fixed mistake; don't dwell on it. If it was a really big screw up, you've got damage control to do.
4. Small mistakes, notify when it's down and when it's fixed. Big mistakes, notify when any milestones to the solution have been reached.

I prefer my vendors to provide too much information about downtimes. But many businesses just can't or they're zipped up by the lawyers. Consult your lawyer/insurance if you have any doubts.