Added upgrade instructions for 0.4.0 [skip ci]

CHANGELOG.md

@@ -1,5 +1,7 @@
 ## 0.4.0 (unreleased)
 
+If upgrading with Postgres < 13, see [this note](#040).
+
 - Changed text representation for vector elements to match `real`
 - Changed storage for vector from `plain` to `extended`
 - Increased max dimensions for vector from 1024 to 16000

README.md

@@ -277,6 +277,16 @@ ALTER EXTENSION vector UPDATE;
 
 ## Upgrade Notes
 
+### 0.4.0
+
+For Postgres < 13, remove this line from `sql/vector--0.3.2--0.4.0.sql`:
+
+```sql
+ALTER TYPE vector SET (STORAGE = extended);
+```
+
+Then run `make install` and `ALTER EXTENSION vector UPDATE;`.
+
 ### 0.3.1
 
 If upgrading from 0.2.7 or 0.3.0, recreate all `ivfflat` indexes after upgrading to ensure all data is indexed.

sql/vector--0.3.2--0.4.0.sql

@@ -1,7 +1,7 @@
 -- complain if script is sourced in psql, rather than via CREATE EXTENSION
 \echo Use "ALTER EXTENSION vector UPDATE TO '0.4.0'" to load this file. \quit
 
--- comment out this single line for Postgres < 13
+-- remove this single line for Postgres < 13
 ALTER TYPE vector SET (STORAGE = extended);
 
 CREATE FUNCTION vector_accum(double precision[], vector) RETURNS double precision[]