I'm migrate my solr environment from 6.3 to 7.2 and walks trough all the config files. In 6.3 I have a lot of date files, using the tdate filedType, which uses solr.TrieDateField.
<fieldType name="tdate" class="solr.TrieDateField" positionIncrementGap="0" docValues="true" precisionStep="6"/>
In Solr 7 the tdate field is no more part of the default schema file. Instead of tdate, solr 7 seams to use pdate:
<fieldType name="pdate" class="solr.DatePointField" docValues="true"/>
Looking at this "Solr 7 fieldTypes doc" It seams like tdate is no more avaliable in solr 7.x
Can and should I change all the fileds using tdate to pdate?
First, if you want, you can still use TrieDateField if you want not to change anything. It deprecated, but not removed. If this declaration
<fieldType name="tdate" class="solr.TrieDateField" positionIncrementGap="0" docValues="true" precisionStep="6"/>
is missing in your schema, add it.
But, can you change to pdate? Sure, if it is easy to reindex for you, you can change and reindex. Should you? The newer type is more efficient, but for some usecases the new types were less performant than the older one, if you have a good testbed that reflect your real world usage, the best thing would be to benchmark both, if the newer ones perform at least as well as the older ones, I would say, upgrade.