CoffeeCake

For clarity, the Marketplace integration in 4.5 is available and works in a test installation, using the -TESTINSTALL license, so long as your installation is reachable from the Internet. In other words, IPS needs to be able to initiate a connection to your install. If your test install is on your local machine or inside a corporate network and you haven't made provisions with your firewall or router so that it is reachable from the public internet, the integration does not work. Remember, if you do this, you need to secure your test install behind additional HTTP authentication (i.e.  htpasswd).
@Stuart Silvester goes into that here:
What doesn't presently work is:
Adding plugins and applications from the IPS Marketplace to localhost installations (that don't have the -TESTLICENSE and aren't accessible to the Internet as above). These are typically used by developers to author themes, plugins, and applications and then redistribute them privately to test and production environments, or offer them from the IPS Marketplace to others for free or at a price. Prior to this unannounced change with 4.5, you could run multiple local virtualized installs for testing and development purposes and install third party applications and plugins from the Marketplace that live only on your local machine and are not accessible from the internet. You might want to test your own local changes against an install that has the various third-party integrations you've purchased from Marketplace present and ensure there aren't any compatibility issues or things that break due to conflicts, as an example, or to ensure a theme properly works with third-party integrations. Now, you cannot get these plugins and applications into a localhost install without obtaining the files from the developer directly. The ability to download, inspect, audit, or commit to backup file repository any marketplace applications and plugins prior to installing it in any environment. This is typically done to ensure compatibility with other modifications, perform code audits and ensure that best practices have been implemented by the developer, identify any potential issues, make backups of critical functionality, retain version history in a source control system (such as git), identify bugs, etc. If the things that aren't working in the two bullet points above are important to you, @Lindy and the IPS team welcome your feedback.
For us, we do local development on a local install that lives in virtual machines on our development computers. We commit our work into source control and then when we've reached a place that we're ready to do user acceptance testing, we promote those changes into our -TESTINSTALL license that our testers can access. Once we're confident things are working there, we promote to production.
This is probably not the sort of rigor most causal administrators would bother going through, and likely not done by IPS Cloud customers. I'm not even sure they have access to run a local environment without getting a self-hosted license.

For clarity, the Marketplace integration in 4.5 is available and works in a test installation, using the -TESTINSTALL license, so long as your installation is reachable from the Internet. In other words, IPS needs to be able to initiate a connection to your install. If your test install is on your local machine or inside a corporate network and you haven't made provisions with your firewall or router so that it is reachable from the public internet, the integration does not work. Remember, if you do this, you need to secure your test install behind additional HTTP authentication (i.e.  htpasswd).
@Stuart Silvester goes into that here:
What doesn't presently work is:
Adding plugins and applications from the IPS Marketplace to localhost installations (that don't have the -TESTLICENSE and aren't accessible to the Internet as above). These are typically used by developers to author themes, plugins, and applications and then redistribute them privately to test and production environments, or offer them from the IPS Marketplace to others for free or at a price. Prior to this unannounced change with 4.5, you could run multiple local virtualized installs for testing and development purposes and install third party applications and plugins from the Marketplace that live only on your local machine and are not accessible from the internet. You might want to test your own local changes against an install that has the various third-party integrations you've purchased from Marketplace present and ensure there aren't any compatibility issues or things that break due to conflicts, as an example, or to ensure a theme properly works with third-party integrations. Now, you cannot get these plugins and applications into a localhost install without obtaining the files from the developer directly. The ability to download, inspect, audit, or commit to backup file repository any marketplace applications and plugins prior to installing it in any environment. This is typically done to ensure compatibility with other modifications, perform code audits and ensure that best practices have been implemented by the developer, identify any potential issues, make backups of critical functionality, retain version history in a source control system (such as git), identify bugs, etc. If the things that aren't working in the two bullet points above are important to you, @Lindy and the IPS team welcome your feedback.
For us, we do local development on a local install that lives in virtual machines on our development computers. We commit our work into source control and then when we've reached a place that we're ready to do user acceptance testing, we promote those changes into our -TESTINSTALL license that our testers can access. Once we're confident things are working there, we promote to production.
This is probably not the sort of rigor most causal administrators would bother going through, and likely not done by IPS Cloud customers. I'm not even sure they have access to run a local environment without getting a self-hosted license.

@Saurabh Jain there is also a known issue where available updates will not appear immediately depending on the number of things you have installed from marketplace. You may need to go to ACP > Settings > Applications and click the "Check for updates" a number of times before available updates appear (we had to click it 8-9 times in testing for our installs). Once they're available, you'll see the counter on the application/plugin area increment and show that updates are available, and a link next to the application/plugin that says "Upgrade" which you can click to begin the upgrade process.
We don't use themes from the marketplace, so I'm not sure if the same applies there.

I know it's a bit confusing and I will be clearing it up but you need to enable the "create topic" setting as well. Even if only using the post reply feature.
I will be looking through the beta soon but so far I haven't had any reported issues.
I'm not sure what else to suggest at this point. Are you planning to upgrade to IPB 4.5 soon? As they may have improved the position I can hook into new signups.

Thanks for the update!

I noticed that in a few places you're hacking around support for lower case (http2) headers, and there are a bunch of places where you don't handle them correctly. Is there a reason that you're not lowercasing all headers when storing the headers (and also storing the originals for back compat)? eg there are a bunch of places where you test for $response->httpHeaders['Location'] || $response->httpHeaders['location'], but if you standardise them then you can just test one. You already standardise location, but you may as well do it for everything then deprecate the upper case ones.

Absolutely a necessity to support multiple localhost development environments and to support the download of application/plugins directly from the IPS marketplace as existed in 4.4 and earlier. The inability to download files directly from the marketplace limits severely limits those that have installations that are not accessible from the outside internet, whether that be an internal corporate install or various development / virtualized environments.
It also prevents administrators and security folks from being able to audit applications and plugins prior to installation in any environment. At present, one must install an application/plugin prior to being able to review. In the past, we've purchased plugins/applications that upon inspection of the downloaded file, we found that there were breaking changes that did not follow IPS development guidelines and that would have resulted in a degradation of service in our production environment. Without inspecting those files in advance, we would have not been able to identify these issues.

Absolutely a necessity to support multiple localhost development environments and to support the download of application/plugins directly from the IPS marketplace as existed in 4.4 and earlier. The inability to download files directly from the marketplace limits severely limits those that have installations that are not accessible from the outside internet, whether that be an internal corporate install or various development / virtualized environments.
It also prevents administrators and security folks from being able to audit applications and plugins prior to installation in any environment. At present, one must install an application/plugin prior to being able to review. In the past, we've purchased plugins/applications that upon inspection of the downloaded file, we found that there were breaking changes that did not follow IPS development guidelines and that would have resulted in a degradation of service in our production environment. Without inspecting those files in advance, we would have not been able to identify these issues.

The default behavior was changed in the default theme. 4.4 had an edit link down by quote, and beginning with 4.5 it's been moved into the ellipsis in the corner now.
You'd need to customize your theme (or develop a theme hook) to restore it to the previous position. 

Correct, it has happened to me here on IPS...before purchasing an addon I asked if the addon can do x, developer says yes, purchased addon and found it doesn't, asked developer for refund and developer says he can't give refunds.
I have been bitten by so many developers over many many years on vBulletin, on IPS and on Xenforo...it's all the same. BUT, the biggest point I was making here is that I prefer to test addons on my own PC before testing them online. There is so much involved in testing them that I can't be doing it online...to begin with I need to take a current snapshot of my site every time and doing it online with the way my hosting is, is an extreme pain in the but compared to just downloading a copy, which also serves as a local offsite backup, and setting it up in my local xampp environment. There I can test everything without impacting my site and especially my hosting setup. By not being able to do this increases the cost of ownership of IPS dramatically for me especially in time and risk...why do you think my main site is still using Xenforo, because my main site deserves my attention the most and XF allows me to do things so much easier, quicker and better. Already the decision of comparing Xenforo vs IPS is an extremely hard decision to make, IPS are now making the decision much easier and that is not to IPS's favour in my own opinion and solution needs. The thing is, I will always speak up...but what about all those that don't and thus IPS never hear about their wrong decisions. Develop to what your customers tell you and you will always only have those customers, develop to what your non customers also want, and you may increase your customer base two-fold. In other words, If I didn't say something and just said oh stuff it and drop IPS, then you would never know how you could have had another customer...and I have 2 licenses (I have 3 XF licenses) so how many more licenses has IPS not sold??? Cost of ownership (time and inconvenience) has dramatically increased for me with IPS but at least I will say something about it...will you at least listen???

I don't think it's the issue that you can't point to the marketplace. It's the issue that you can't download and inspect the packages directly from IPS any more. There's now a requirement that the test install have internet access and that you install things before inspecting them, and for localhost installs, you can't install and test applications and plugins published by the community (without a roundabout process of installing in test and then extracting the resource).
For many communities, plug and play is probably just fine. But it's not serving the needs of those clients that have more stringent policies or requirements that they follow in the development lifecycle. Now, there's an extra step of using a test install to acquire files rather than being able to download and inspect them as before (or put them in a virtual localhost environment).
The IPS marketplace should have a download button for 4.5 resources, and have its current integration as well. Go install from your ACP, or download here. That would be ideal.
Just to add for context, we've purchased, downloaded, and installed a few applications and plugins from IPS Marketplace that, when tested in our local environments, we quickly identified conflicts, issues, and breaking changes that would degrade our member experience and/or simply not work at the scale of a community the size of ours. We identified issues that would have otherwise taken down our production copy and/or production installs due to things like altering the core_members table rather than having an application/plugin specific table. Whatever checks of things (if any--I'm not sure) happening at IPS, they're insufficient for our needs, and we have a duty to our stakeholders to test things and ensure they're ready for our environment and configuration.
This change is an obstacle to that process. We have a workaround, yet it's needlessly causing us to install things in test and have to revert that environment after the fact when our workflow of installing in a local dev first and doing comparisons was much preferred.

Highly recommend @Adriano Faria for any of your modification needs. Let's keep him safe!

I do permit BUT I leave pretty well clear that I don't support ANY modification. User is allwed to do it but he's on your own... including current supported files. Funny because even having this in the Terms, people still review your file with 1 star because you don't support. 😆

This I find more than reasonable, @Adriano Faria. I would never expect a developer to go out of their way to help me with personal modifications that weren't explicitly supported by the software or official documentation. It's unfortunate some of your clients don't see it this way. I appreciate you continuing to develop modifications and allowing modifications despite this.

Throw in an option to disable quicksand and I'm in.
 

To be honest, apps and plugins that get abandoned are one prime reason we need a way to sensibly obtain the files to fix issues ourselves if we want. I know many wont have the skills to do that but as someone who has patched abandoned plugins for vbulletin for years I think we as customers of plugins should have some ability to get plugins manually.
We are customers, pirates will always find a way to do what they want and they arent all lost sales but causing issues for customers will lead to lost sales. Always think of those that are prepared to pay over the concerns of those that would never pay.

It would be nice to see a 'manage purchases' as an option, just like the client page. Can keep up to date with all the apps/plugins in one place.

Throw in an option to disable quicksand and I'm in.
 

Actually, I would expect quite the opposite. Just as with the movie industry who imposed non-skippable scenes on retail DVDs, or the gaming industry whose certain games impose constant Internet-based license validation for single-player mode under the guise of an "enhanced experience," the nulled/cracked/ripped version provides the best experience. It's only the paying, honest customers who get hurt and punished by these types of imposed restrictions.

Such is the risk we run relying on resources sold by others, and why it's important to be able to pick up maintenance of critical functionality for your community that you've come to rely on should others drop the ball (or simply be unable to) continue maintaining what you've come to depend on. Helpful to that effort is the ability to download and maintain code repositories of purchased plugins, applications, themes, etc. @Lindy welcomes your letting him know that this niche feature is something you'd appreciate to help guide potential future restoration of that ability.
It would be very nice to see things in the marketplace marked as abandoned or no longer maintained. Xenforo's market for modifications seems to do that at a cursory glance, yet I'm not a customer of theirs. It would be very very nice to have built in provisos that encourage developers to setup mechanisms that take effect when their resources are no longer able to be maintained by them. Suppose @Adriano Faria decides to go off the grid and move to a private island... or the private island swallows him whole in a tragic turn of events. What happens to the things so many have come to depend on?
You purchase things right now at your own risk, with no guarantee that anything will work or that it won't break your community, or that it will be maintained in any future capacity. When thinking about third party things, it's important to consider those inherent risks vs. the benefits of the addon/modification. It's a good idea to have plans in place for contingencies if those are things that are important to you. And, for goodness sake, test things in your test install before installing them on your live site. Hopefully those in the cloud have test installs included.
To borrow an analogy, "Apple," (IPS) in this instance, would suggest you download another similar app or hire someone to take on recreating your abandoned resource and let the "marketplace" of developers here sort that out for you. Things will sell at the rates people are willing to pay for them--you need to consider if it's worth the listed price to you along with the risks of depending on someone else when it comes to things like upgrading to new versions, fixing vulnerabilities, and very real risks of developers falling into quicksand. Before purchasing, realize that short of getting a download at that moment, all bets are off going forward.

I don't think it's the issue that you can't point to the marketplace. It's the issue that you can't download and inspect the packages directly from IPS any more. There's now a requirement that the test install have internet access and that you install things before inspecting them, and for localhost installs, you can't install and test applications and plugins published by the community (without a roundabout process of installing in test and then extracting the resource).
For many communities, plug and play is probably just fine. But it's not serving the needs of those clients that have more stringent policies or requirements that they follow in the development lifecycle. Now, there's an extra step of using a test install to acquire files rather than being able to download and inspect them as before (or put them in a virtual localhost environment).
The IPS marketplace should have a download button for 4.5 resources, and have its current integration as well. Go install from your ACP, or download here. That would be ideal.
Just to add for context, we've purchased, downloaded, and installed a few applications and plugins from IPS Marketplace that, when tested in our local environments, we quickly identified conflicts, issues, and breaking changes that would degrade our member experience and/or simply not work at the scale of a community the size of ours. We identified issues that would have otherwise taken down our production copy and/or production installs due to things like altering the core_members table rather than having an application/plugin specific table. Whatever checks of things (if any--I'm not sure) happening at IPS, they're insufficient for our needs, and we have a duty to our stakeholders to test things and ensure they're ready for our environment and configuration.
This change is an obstacle to that process. We have a workaround, yet it's needlessly causing us to install things in test and have to revert that environment after the fact when our workflow of installing in a local dev first and doing comparisons was much preferred.

Absolutely a necessity to support multiple localhost development environments and to support the download of application/plugins directly from the IPS marketplace as existed in 4.4 and earlier. The inability to download files directly from the marketplace limits severely limits those that have installations that are not accessible from the outside internet, whether that be an internal corporate install or various development / virtualized environments.
It also prevents administrators and security folks from being able to audit applications and plugins prior to installation in any environment. At present, one must install an application/plugin prior to being able to review. In the past, we've purchased plugins/applications that upon inspection of the downloaded file, we found that there were breaking changes that did not follow IPS development guidelines and that would have resulted in a degradation of service in our production environment. Without inspecting those files in advance, we would have not been able to identify these issues.

I don't think it's the issue that you can't point to the marketplace. It's the issue that you can't download and inspect the packages directly from IPS any more. There's now a requirement that the test install have internet access and that you install things before inspecting them, and for localhost installs, you can't install and test applications and plugins published by the community (without a roundabout process of installing in test and then extracting the resource).
For many communities, plug and play is probably just fine. But it's not serving the needs of those clients that have more stringent policies or requirements that they follow in the development lifecycle. Now, there's an extra step of using a test install to acquire files rather than being able to download and inspect them as before (or put them in a virtual localhost environment).
The IPS marketplace should have a download button for 4.5 resources, and have its current integration as well. Go install from your ACP, or download here. That would be ideal.
Just to add for context, we've purchased, downloaded, and installed a few applications and plugins from IPS Marketplace that, when tested in our local environments, we quickly identified conflicts, issues, and breaking changes that would degrade our member experience and/or simply not work at the scale of a community the size of ours. We identified issues that would have otherwise taken down our production copy and/or production installs due to things like altering the core_members table rather than having an application/plugin specific table. Whatever checks of things (if any--I'm not sure) happening at IPS, they're insufficient for our needs, and we have a duty to our stakeholders to test things and ensure they're ready for our environment and configuration.
This change is an obstacle to that process. We have a workaround, yet it's needlessly causing us to install things in test and have to revert that environment after the fact when our workflow of installing in a local dev first and doing comparisons was much preferred.

I'm hopeful this is an oversight that will be promptly addressed prior to release.

I don't think it's the issue that you can't point to the marketplace. It's the issue that you can't download and inspect the packages directly from IPS any more. There's now a requirement that the test install have internet access and that you install things before inspecting them, and for localhost installs, you can't install and test applications and plugins published by the community (without a roundabout process of installing in test and then extracting the resource).
For many communities, plug and play is probably just fine. But it's not serving the needs of those clients that have more stringent policies or requirements that they follow in the development lifecycle. Now, there's an extra step of using a test install to acquire files rather than being able to download and inspect them as before (or put them in a virtual localhost environment).
The IPS marketplace should have a download button for 4.5 resources, and have its current integration as well. Go install from your ACP, or download here. That would be ideal.
Just to add for context, we've purchased, downloaded, and installed a few applications and plugins from IPS Marketplace that, when tested in our local environments, we quickly identified conflicts, issues, and breaking changes that would degrade our member experience and/or simply not work at the scale of a community the size of ours. We identified issues that would have otherwise taken down our production copy and/or production installs due to things like altering the core_members table rather than having an application/plugin specific table. Whatever checks of things (if any--I'm not sure) happening at IPS, they're insufficient for our needs, and we have a duty to our stakeholders to test things and ensure they're ready for our environment and configuration.
This change is an obstacle to that process. We have a workaround, yet it's needlessly causing us to install things in test and have to revert that environment after the fact when our workflow of installing in a local dev first and doing comparisons was much preferred.