You can transfer your learning material between SuperMemos via XML
Core XML exchange serves only inter-platform communication
Text filters in XML export
You can transfer between SuperMemo for Pocket PC and SuperMemo for Windows
Merging learning material on Pocket PC
Generating SuperMemo XML files manually
Special repetition case in XML import
XML data exchange will help transfer the learning process between platforms
Error: Cannot guess the correct repetition history
Problems with importing XML from Excel

You can transfer your learning material between SuperMemos via XML
(Pengyou, Apr 05, 2005, 16:20:52)
Question:
I have seen the phrase "XML file" all over the place with. I did a Google on it and got too many responses to even bother trying to read. Can you give me a quick and dirty?
Answer:
When googling for general terms, always add "supermemo" to your search string. In the context of SuperMemo 2004, "XML file" means: your learning material exported from SuperMemo with File : Tools : Export : As XML (or other options that export in XML format). Material in the form of the XML file, can be used, for example, to transfer your learning process from SuperMemo 2004 to SuperMemo for Pocket PC back and forth

Core XML exchange serves only inter-platform communication
(Edele'nyi Gyula, Hungary, Aug 02, 2004, 01:00:14)
Question:
I imported some formatted Word docs into SuperMemo, then exported as XML. Then tried to import it as XML into another collection. The simple Q&A XML export-import worked, but the Word docs hadn't come back well
Answer:
SuperMemo 2004 implements only Core XML data. The core specification was intended for data exchange between various SuperMemos. Only SuperMemo for Windows uses non-folder topics and incremental reading. For this reason, topic articles are not part of Core XML. Use XML to exchange data between platforms. To exchange data between collections created with SuperMemo 2004, you can still use the old text transfer methods (e.g. Tools : Transfer in the browser)

Merging learning material on Pocket PC
(Bill Sanchez, Thu, Jun 20, 2002 4:22)
Question:
I am using SuperMemo CE on my Pocket PC. I have created questions in different files. I would like to combine all the questions into one file now
Answer:
You could export your files as XML and merge the XML files. If you import it back to SuperMemo for Pocket PC, your collections will have been merged

Special repetition case in XML import
(Beta-piwo, Jul 05, 2004)
Question:
I got a "special repetition case" message in XML import. What does it mean? 
SPECIAL REPETITION CASE CONSIDERED 
Recency=62.5% 
Interval Boost=1.3% 
Repetition Sequence=100% 
Advice=62.19% 
UPDATE RECOMMENDED 
Interval protectively changed from: 21 to 20 
INTEGRATING {2}:Item #232566: The röntgen is a unit of dosage of X-rays or gamma radiation 
Reps: 1->2 
Lapses: 0->0 
Interval: 23->20 
Last rep: 12.06.2004->22.06.2004 
Next rep: 05.07.2004->12.07.2004 
UF: 23->2 AF: 3->3.274
Answer:
This message will appear if you duplicate repetitions in two collections. It may also appear if you delay repetitions and import of your XML learning process over a longer period (beyond one month). In such cases SuperMemo will try to guess what has caused data discrepancy, take the optimum course of action so that to minimize the cost in learning time. 

In this specific case, SuperMemo compared the recency of the two repetitions, the change to item's interval, as well as the sequence of repetitions executed. In the end, it concluded (preponderance 62.19%), that the repetition update should be executed. However, it decided to reduce the interval from 23 days (in the source collection) and 21 days suggested by the XML file to 20 days. In the end, you will find the repetition recorded as executed on Jun 22, 2004 (as opposed to Jun 12) with the interval of 20 days, and the next repetition date scheduled on Jul 12, 2004

You can transfer between SuperMemo for Pocket PC and SuperMemo for Windows
(Miloslav Skácel, Czech Republic, Thursday, November 07, 2002 11:10 PM)
Question:
Is it possible to transfer my knowledge between SuperMemo for Pocket PC and SuperMemo for Windows?
Answer:
Yes. XML data exchange makes it possible to exchange questions-and-answers as well as the learning process. See: Revolution in the Pocket for a detailed algorithm

XML data exchange will help transfer the learning process between platforms
(leopold16dk, Jun 13, 2002)
Question:
Is it possible to convert my learning process from SuperMemo for Palm Pilot to SuperMemo for Pocket PC?
Answer:
Currently you can only transfer question&answer material between handheld platforms. However, a comprehensive XML-based data exchange for all SuperMemo desktop, handheld and on-line platforms is in design

Text filters in XML export
(Michael, Jun 14, 2004, 08:23:13)
Question:
What is the purpose of the filter dialog box in XML export?
Answer:
Text filters in SuperMemo can be used to pre-process texts before using export options. Using filters is optional. Without filtering, the exported text will look the exactly same as the text in the collection

Error: Cannot guess the correct repetition history
(yahoogroups.com, Saturday, September 24, 2005 1:41 PM)
Question:
Everyday I get 2-3 of these errors when importing my XML file from SuperMemo CE to SuperMemo 2004 (with File : Tools : Import : Learning process : XML file): 

Cannot guess the correct repetition history 
CANNOT INTEGRATE: Item #11553: Hier ist [a good] [...] Wein. 
Reps: 5->7 
Lapses: 0->0 
Interval: 22->60 
Last rep: 01.09.2005->23.09.2005 
Next rep: 23.09.2005->22.11.2005 
UF: 1.048->2.766 
AF: 5.383->5.378
Answer:
SuperMemo 2004 allows of simultaneous repetitions of the same material in SuperMemo 2004 and on a Pocket PC device. It also attempts to heuristically fill gaps in repetition history if more than one repetition was made on Pocket PC. If reconciling data from two collections is not possible, it may display "Cannot integrate" error (in this case "Cannot guess the correct repetition history"). For example, it could happen if the interval between repetitions was negative or zero (e.g. if you use Midnight Shift in SuperMemo 2004, etc.). 

Each time you get this error, you can either ignore it (repetition made on Pocket PC will be discarded) or go to the element in question and manually force a repetition (Ctrl+Shift+R) or choose a new interval (Ctrl+J). This would be a reason for worry only if a large proportion of items showed such problems (e.g. due to a wrong setting of the date in your computer).

Simultaneous repetitions are not recommended as these introduce some confusion in the learning process. You can move between platforms freely, but then you should either make repetitions on one platform only or use subsets to exclude Pocket PC repetitions from SuperMemo 2004 repetition set while working on Pocket PC

Problems with importing XML from Excel
(Stefan, Singapore, Jun 22, 2005, 14:42:29)
Question:
I want to add new words to Pocket PC by working on a desktop computer. I have opened an XML file from Pocket PC in Excel and added new words. After this I have transferred the XML file back to the Pocket PC, but the import did not work.
Answer:
If you want to create your word pairs on a desktop computer, use Q&A file format. XML format is useful only if you want to create your material in SuperMemo 2004. You cannot import XML files from Excel as it uses a completely different file definition (DTD). XML format definition is SuperMemo-specific and is used only for transferring files between different versions of SuperMemo

Generating SuperMemo XML files manually
(Xavier Verges Farrero, Apr 26, 2005, 00:40:32)
Question:
I would like to generate XML files myself. Is the ID only important within a given xml file, or is it related to some other data? Could I feed SuperMemo with generated xml files that would not have the LearningData elements?
Answer:
You can produce XML files for SuperMemo using any tool of your choice. Element IDs are currently important only if you wish to re-import material exported from SuperMemo 2004 back to your SuperMemo 2004 collection. If you skip them, new elements will be created. If you skip LearningData, elements will be treated as pending (i.e. not learned)