Hi @trafalgarlaw , I agree that this is something of a problem.
As @sanket_2012 mentions, the change log for each release should contain the information about the node changes for that release but whilst this is good for a single version update, it is difficult to find all the differences across multiple versions and minor releases. So if you are jumping from 4.6.5 to 5.3, there may be a large number of nodes that have been renamed, and you’d have to scour every change log to find them. It is becoming increasingly difficult to keep up, especially when here on the forum we still try to support people using both 4.x and 5.x.
I would ideally like to see a single “node encyclopaedia” which details the evolving names of nodes across the different KNIME versions. I suspect though that doing this retrospectively would be challenging.
Perhaps an idea would be that ongoing, such a page could exist, and would detail nodes, something like this:
| 4.7 | 5.0 | 5.1 | 5.2 | 5.3 |
|---|---|---|---|---|
| Insert Column Header | Column Renamer (Dictionary) [modern UI] | |||
| Extract Column Header | Column Name Extractor [modern UI] | |||
| Round Double | Number Rounder [modern ui] | |||
| Column Rename | Column Rename (deprecated) / Column Renamer [modern ui] | |||
| Joiner | Joiner (deprecated) / Joiner [modern ui] | |||
| Row Filter | Row Filter [modern ui] | |||
| Row Splitter | Row Splitter [modern ui] |
The above is just for example purposes, and far from perfect (and may even be factually inaccurate 
)
I wonder if such a table could be produced using a workflow that collects together the information from different KNIME AP changelogs and tabulates the names of the nodes that are new, renamed, deprecated and so on.
It rather depends on whether all the change logs are in a similar and digestible format. But possibly this could be added to the Suggestions for Just KNIME It! challenges
Another thought is that on the KNIME Hub itself, where a node is listed, perhaps it could be adapted so that it could contain a “previously/also known as” section, which could potentially be searchable.
There are many scenarios concerning node changes and each has the potential to bring some difficulty for users old and new.
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Sometimes a node’s name is just changed to (legacy), in which case it would be nice to see a single point of reference that tells you what to use instead that is “non-legacy” going forward.
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Sometimes a node is deprecated and a new replacement node appears, e.g. a modern UI version, such as in the case above of Column Rename and Joiner. Other times a replacement modern UI version appears, but there is no deprecated version, presumably because the new version is considered fully backward compatible with the Classic UI version that it replaces, and so will continue to work if it were again opened in an older KNIME version.
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In other cases a node is simply renamed. This can be a challenge when you use a node infrequently. I’ve had occasions when I have an “I’m sure there used to be a… node” moment. A search for the old name on the community hub often (but I believe doesn’t always) reveal the node with its new name.
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In the case of Round Double (replaced by Number Rounder in 5.3), functionality that was clearly present on the original is now “hidden” in advanced settings as “legacy” and so it is not immediately apparent that the new node fully provides the original functionality, but there appears to not be a deprecated version of the original, so I wonder whether the “legacy” functionality is going to move to another node in future, or what the story is there!
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For other nodes (Row Filter, Row Splitter), the new version is intended to be “equivalent” functionality but has been ported to the modern ui and the config has changed out of all recognition.
All of the above scenarios (and probably more) make it challenging to “keep up” without there being some easily accessible reference documentation that spans multiple KNIME versions.
Somebody new to KNIME reading a post based on KNIME 5.2, looking at how to configure the Row Filter node in their newly downloaded KNIME 5.3 may be bewildered as to why the node looks nothing like the screenshots they see on the forum!
An old-hand who has finally made the jump from KNIME 4.7.8 straight to 5.3 (because the new workflow monitor excites them 
), and just trying to write a workflow based on how they’ve done something similar before will perhaps be baffled when they cannot find the “Insert Column Header” node. Without knowing specifically when it changed its name, where do they go to find this out?
In terms of “nodes not working any more”, if you come across something in that category, then I believe that would be considered to be a bug.
Where nodes are updated or replaced in newer versions, the replacements should be backward-compatible, but I guess that can only occur up to a point. If you leap forward a sufficient number of versions, I would guess that some nodes that have become legacy/deprecated in an intervening releases might eventually disappear altogether.
That said, whilst writing this, and researching nodes in KNIME 5.3, I was surprised to find no fewer than 4 joiner nodes (not including the DB Joiner):
The top left node shares the same icon as the new Joiner node and is the most recently deprecated version. The lower two Joiner (deprecated) nodes predate my own use of KNIME, and I don’t think I have ever seen or used those two!
When you bring an existing workflow from KNIME 4.7 to a new version such as KNIME 5.1, the system should adjust the nodes automatically to use any replacements
e.g. Take this workflow from KNIME 4.7
If that is opened in KNIME 5.1 it will appear like this:
Likewise, an example I used recently on another post… this KNIME workflow from 5.2 …
is adapted when opened in 5.3…
Sorry I cannot be of any more help, but I sympathise with your comments. The change logs as mentioned are the place to find changes in each individual release, and searching for an old node name on the KNIME Community Hub can sometimes lead you to the new variant of the renamed node.