PQ Docs: add note about upgrading

[yaauie]

Since the PQ was released as GA in 5.4, to ensure that the note shows up on generated docs pages, this note on upgrading should be back-ported to every major/minor branch since:

• 6.x,
• 6.3,
• 6.2,
• 6.1,
• 6.0,
• 5.6,
• 5.5, and
• 5.4

[yaauie]

Notes:

• Is my relative link the correct syntax?
• For back-port targets prior to 6.3, should the relative link point to the 6.3 upgrade guide?

[karenzone]

@yaauie WRT "Notes"

Is my relative link the correct syntax?
For back-port targets prior to 6.3, should the relative link point to the 6.3 upgrade guide?

Currently the text you're referencing is only in 6.2 and 6.3, so the link will work only for those versions. We've just recently decided to add it to 6.x, but as of this moment, I haven't added it.

Having older versions point to 6.3 feels wrong, but this is a crazy situation and might make sense.

[karenzone]

I was concerned about having outdated info saying that you could upgrade with PQ running, even for older versions. I'm in the process of back-porting content. When done, I'll test your link.

[dedemorton]

I think it's going to be very weird to mention 6.3.0 in releases that occurred prior to 6.3.0. I would remove the mention of 6.3.0 from the note all together and make sure the note shows up in all relevant versions (where the queue.drain option exists) up to, but not including, the version where draining the queue is no longer required.

[karenzone]

Please pardon my delay in getting back to you. I had to add new content for you to link to, and make sure that the wording made sense in context of each version.

• WRT DeDe's note ^^ about mentioning 6.3 specifically. I agree that we can delete the version number so that your content works for all versions. We can control the messaging based on the branches we merge into.
• I added a new anchor [[drain-pq]] for the "Drain the Persistent Queue" topic. You can link to the content like this: <<drain-pq,drain the queue>>.
• We shouldn't merge this into 5.4. According to the doc, the queue.drain option wasn't added until 5.5. Regardless, the PQ was added in 5.4, so no need to talk about upgrading it in 5.4 upgrade doc.
• I believe you need to remove the + before the second note.

[karenzone]

For later versions, we removed the recommendation to drain the queue before upgrade. amd 6.x is no longer supported. We can close this.