investigate update to MEI 5

[peterstadler]

• check MerMEId MEI examples on how those might be updated
• check MerMEId template
• check forms(?)

decide whether to provide only MEI 5, or 4, or both options in the MerMEId

• Convert sample data into MEI 5.0 #202
• Update attribute list to MEI 5.0 #203
• add check for version to file-load functions #204
• update README for update to MEI5 and give some advice on migration #205
• update properties.xml file (updates footer automatically)
• add check to post-install-hook for MEI4 files and issue warning to logs #206

[daniel-jettka]

Differences MEI 4 to MEI 5

• sample data validated against MEI 5.0 schema
• only @meiVersion and @key.sig differ
• @key.sig can occur in incipit in header or in music part of MEI file

Conclusion
-> These are not processed by MerMEId, so no technical issue.
-> So an update to MEI 5 data seems technically straightforward and wouldn't break any MerMEId features

Thoughts

• not sure if it is a good idea to have and support files with different MEI versions in one instance...
• how to deal with existing MerMEId instances and MEI corpora

Options:
(a) have different MerMEId releases
(b) define global setting for MerMEId startup to set supported MEI version

• how to deal with non-compliant files...
• warning (process anyway)?
• error (block processing)?
• supply info/facility for upgrade?
  (c) one MerMEId that supports both versions simultaneously
• display version of files sonwhere?

[daniel-jettka]

Decided in community meeting (25.04.2024):

• move from MEI 4 to 5 from new major release
• no further support of MEI 4

[daniel-jettka]

grep -R "MEI 4" *

data/nielsen_cnw0129.xml:

Transform from MEI 4.0.0 to 4.0.1

properties.xml: v. @repository.version@ for MEI 4.0.0
properties.xml:

v. {$config:version} for MEI 4.0.0

README.md:As of March 2019 MerMEId supports MEI 4.0.0.
style/mei_to_html.xsl: Conversion of MEI 4.0.0 metadata to HTML using XSLT 2.0