-reindex flag needed when switching between latest github self complile and 0.16.3 binary

As stated, I'm using electrum personal server, which needs -txindex=1
When I switched between the latest self compiled client and 0.16.3 binary, upon start up, it shuts down, the debug log gives a notice to run the -reindex flag. (I just ran -reindex on the other client half of the day, so back to square one)
Not sure if this is intended behaviour.

[achow101]

The txindex has changed for 0.17 since 0.16.x. 0.16.3 still has the old txindex format so it will not be able to understand the new txindex created by 0.17. It will need to rebuild it itself, thus the need for -reindex.

Have to watch which clients I run on that disk then. Cheers.