A bit more than a year and a half after releasing Lightroom 3, Adobe today has released (the first?) public beta for Lightroom 4.
Lightroom 4 has lots of new big-ticket goodies, including a book module, map module (with geoencoding!), soft proofing, more video support, and a new render engine that takes the dramatic improvements in raw image conversion seen in the Lr2→Lr3 to the next leap. There are also many small improvements sprinkled about.
Adobe's Lightroom-Journal announcement gives some details, but for a comprehensive list of changes, see Victoria Bampton's always-excellent “What's New” post. For tutorials, walkthroughs, and other coverage, see this long list of links maintained by Sean McCormack
Important note: the Lr4 public beta is a “beta” in the true sense: take care to have a backup of any images you apply it to, and don't expect that any work you do with it will carry forward to the real Lr4 when it comes out. Use it to play around with and as a basis to provide feedback (at Adobe's Lr4 beta forums), but it's not intended to be used (or ready to be used) in a production environment.
Lr4 and Plugins
Modern versions of my plugins should work just fine in the Lr4 public beta.
Unlike the last major upgrade (Lr2→Lr3), there's not much new (yet?) for a plugin developer like me. There was a ton of new stuff in Lr3 to occupy my time (most of it came in Lr3's second public beta), and the stress of it eventually overwhelmed me, but in the end it caused me to make beneficial changes to my habits. I'm still developing every day, but with more balance. That, combined with a recent willingness to walk instead of take the car and I'm in pretty good shape, at my lowest weight in a decade (88kg · 195lb · on my 6'4" frame), but you don't want to hear about that, you want to hear about Lightroom...
Lr4 and Geoencoding
The only Lr4-specific change in my plugins so far is in my Geoencoding-support plugin: the silly kludge of “shadow data” that I had to come up with in Lr1 is now gone because Lightroom's plugin infrastructure finally allows me to update the “real” location data.
The Lr4 public beta does not allow you to upgrade an old catalog to Lr4, so there's not yet a need to migrate old shadow data to real data, but I'll build something to handle that before Lr4 proper is out.
I'm absolutely thrilled that Lr4's new Map Module allows geoencoding, in a variety of ways no less (drop-n-drag on a map!), but I'm not partial to how GPS-unit tracklogs are handled, so I'll probably continue to use my plugin to geoencode with them. My plugin also includes a bunch of other geoencoding-related support functions (enhanced reverse geocoding, view locations in KML, etc.) so I expect the plugin to become even more popular: the ease of the Map Module will bring more Lr users to the geoencoding fold.
Lr4 and Plugin Registration
My plugins are free for everyone to use forever, without payment to me or anyone else. However, I do encourage optional registration, which generally costs 1 cent in a PayPal fee. (If you choose to register and choose to include more than PayPal's minimum as a gift to me, PayPal will take its larger cut in fees, and if there's anything left over for me, you have my gratitude.)
However, none of this has anything to do with the Lr4 public beta, since registration is disabled in the public beta. But it does bring up a point that will matter when Lr4.0 proper is released: the plugin registration system that I came up with ties a registration to a Lightroom serial number, but since a major-version upgrade of Lightroom involves a new Lightroom serial number for Adobe, such an upgrade renders all my plugin registrations invalid. That means that folks who want to register my plugins must re-register them after an upgrade.
The hassle factor makes this really unfortunate, but in the end I hope it's not too burdensome, with registrations being optional and 1-cent and all. I'm sure I'll get flooded with messages by folks not understanding what went wrong with their plugin registration, or those who do understand it but don't like it. Let me offer my apologies up front.