diff --git a/.docs/concepts/pid.md b/.docs/concepts/pid.md
index c5d769192cc561add9f9bba795e8ff78f9edd196..e58ed03ac4ac9be57963d0b009fa9ad88642781d 100644
--- a/.docs/concepts/pid.md
+++ b/.docs/concepts/pid.md
@@ -2,6 +2,56 @@
 author: Martin Weise
 ---
 
-## tbd
+## Data Versioning
 
-tbd
+Data is getting bigger and so are expectations of data provisioning in regards to data availability (i.e. immediately
+after quality check and not in snapshot intervals), cost-effectiveness (i.e. no duplication of data), transparent,
+precise citation and many more.
+
+[System-versioned](https://mariadb.com/kb/en/system-versioned-tables/) tables in MariaDB are improved data structures
+that keep track of historical data. For each entry in a system-versioned table, a time period is maintained that denotes
+the validity time span of this tuple from its start to end. Tuples in system-versioned tables are not *actually*
+modified, they are marked as (in-)valid in time periods.
+
+<figure markdown>
+
+| ID | Sensor | Temp | Start | End |
+|----|--------|------|-------|-----|
+| 1  | A      | 23.1 | t1    |     |
+| 2  | B      | 25.8 | t2    |     |
+
+</figure>
+
+Assuming that Sensor A was calibrated wrong and an updated measurement is passed to the system-versioned table, the
+table contents show that the old row with Temp 23.1 is not deleted, but marked as valid in time span (t1, t3). The
+updated row with Temp 22.1 is marked as valid from time span t3 onwards.
+
+<figure markdown>
+
+| ID | Sensor | Temp | Start | End |
+|----|--------|------|-------|-----|
+| 1  | A      | 23.1 | t1    | t3  |
+| 2  | B      | 25.8 | t2    |     |
+| 1  | A      | 22.1 | t3    |     |
+
+</figure>
+
+System-versioned tables are part of the SQL:2011 standard and have been adopted by many database management system
+vendors: MariaDB (10.5 and higher), Google BigQuery, IBM DB2 (12 and higher), SQL Server (2016 and higher), Azure SQL,
+PostgreSQL with [temporal tables extension](https://github.com/nearform/temporal_tables), etc.
+
+## Persistent Identifier
+
+Data in DBRepo always has attached metadata (stored in the [Metadata Database](../../api/metadata-db)). This metadata
+is provided as machine-understandable context in various open-source formats that is available, even when the original
+data is not available anymore due to e.g. a retracted dataset (hence the name **persistent**). A persistent identifier
+globally, uniquely identifies a data record such as:
+
+* Database,
+* Table whose data is continously changed in the background (nature of databases),
+* View who show a denomination, joined schema or aggregated result of tables,
+* Subset which precisely identifies a data record to reproduce the same dataset.
+
+Combining [data versioning](#data-versioning) and queries, subsets can be precisely identified by storing the query
+that creates them and the time when the query was executed. We store both in a table inside the database we call the
+query store.
\ No newline at end of file
diff --git a/.docs/concepts/search.md b/.docs/concepts/search.md
index 8731100f91246b2f56091af373962d30d76796e6..ee738e0bd9e99fb89c4ddf867cfb8600a13f432a 100644
--- a/.docs/concepts/search.md
+++ b/.docs/concepts/search.md
@@ -2,22 +2,16 @@
 author: Martin Weise
 ---
 
-## Index
-
-tbd
-
 ## Document
 
-TBD
-
-## Query
+Each database in DBRepo has their own document where the document id (the identifier of a database in OpenSearch) is
+equivalent to the database id (the identifier of a database in the [Metadata Database](../../api/metadata-db)).
 
 ## Unit Independent Search
 
 Since the repository automatically collects statistical properties (min, max, mean, median, std.dev) in both the
-[Metadata Database](../system-databases-metadata) and the [Search Database](../system-databases-search), a special
-search can be performed when at least two columns have the same semantic concept (e.g. temperature) annotated and
-the units of measurements can be transformed.
+[Metadata Database](../../api/metadata-db) and the Search Database, a special search can be performed when at least two
+columns have the same semantic concept (e.g. temperature) annotated and the units of measurements can be transformed.
 
 <figure markdown>
 ![Two tables with compatible semantic concepts (Temperature) and units of measurement (left is in degree Celsius, right is in degree Fahrenheit)](../images/statistics-example.png)
diff --git a/.docs/concepts/storage.md b/.docs/concepts/storage.md
deleted file mode 100644
index fcc975fab2f20d4f3b3b6b0ebd69b02168227bc1..0000000000000000000000000000000000000000
--- a/.docs/concepts/storage.md
+++ /dev/null
@@ -1,15 +0,0 @@
----
-author: Martin Weise
----
-
-## S3
-
-TBD
-
-## Sidecar
-
-TBD
-
-## Upload
-
-TBD
\ No newline at end of file
diff --git a/.docs/migration.md b/.docs/migration.md
deleted file mode 100644
index e56b88ab8b99fb4cdffc9d68c5db28703f4fdaa8..0000000000000000000000000000000000000000
--- a/.docs/migration.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-author: Martin Weise
----
-
-TBD
\ No newline at end of file
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 605b27a39cfd4da5bf682351ebe00dd2ba2e7669..8322e26eb1201fe2c4429c6eca6cee85d74654b1 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -371,6 +371,7 @@ release-helm:
   only:
     refs:
       - /^release-.*/
+  when: manual
   except:
     refs:
       - release-latest
diff --git a/README.md b/README.md
index e6f58da9748fbf23f034721c7487016e042dc082..1ab1d140ed50d77dbdc7426e10fefe9e53b9eb56 100644
--- a/README.md
+++ b/README.md
@@ -14,7 +14,7 @@ If you have [Docker](https://docs.docker.com/engine/install/) already installed
 with:
 
 ```bash
-curl -sSL https://gitlab.phaidra.org/fair-data-austria-db-repository/fda-services/-/raw/release-1.4.4/install.sh | bash
+curl -sSL https://gitlab.phaidra.org/fair-data-austria-db-repository/fda-services/-/raw/release-1.4.5/install.sh | bash
 ```
 
 ## Documentation
diff --git a/mkdocs.yml b/mkdocs.yml
index 7c5b7e7a6988aea67a866b9d5b2949cdb3584a4e..45e06cbe388165e317e3a520d0b5ad00a8995449 100644
--- a/mkdocs.yml
+++ b/mkdocs.yml
@@ -12,7 +12,6 @@ nav:
     - Help with DBRepo: help.md
     - Installation: installation.md
     - Kubernetes: kubernetes.md
-    - Migration Guide: migration.md
     - contributing.md
   - Concepts:
     - Overview: concepts/index.md
@@ -22,7 +21,6 @@ nav:
     - Monitoring: concepts/monitoring.md
     - Persistent Identifier: concepts/pid.md
     - Search: concepts/search.md
-    - Storage: concepts/storage.md
     - User Interface: concepts/ui.md
   - API:
     - Overview: api/index.md