Shareplex 5.3.0 is architecturally compatible with previous releases. 5.x versions can replicate from lower to higher and higher to lower versions. 4.5 can only replicate to 5.x versions, but 5.x versions can not replicate back to 4.5 due to queue structure difference.
Also, 5.x can replicate to 6.x but 6.x cannot replicate back to 5.x. So the lower-to-higher rule applies to 6.0 as well.
For information about restrictions when replicating between SharePlex versions, refer to the INTEROPERABILITY MATRIX listed below . This is listed in the Release Notes as well.
Source replicating to... Target
5.3 5.0 ,5.2,5.1, 5.3
5.2 5.0, 5.2 ,5.1, 5.3
5.1 5.0, 5.2,5.1, 5.3
5.0 5.0, 5.2,5.1, 5.3
4.5 5.0 ,5.2,5.1, 5.3,4.5
NOTE: You can replicate from 4.0/4.5 to 5.x, but you can not replicate from 5.x to 4.x. You can replicate from 5.x to 6.x but you cannot replicate 6.x to 5.x